diff --git a/.clang-format-ignore b/.clang-format-ignore
index e39e5579504c..eb87ecd42b7a 100644
--- a/.clang-format-ignore
+++ b/.clang-format-ignore
@@ -78,6 +78,7 @@ dom/media/webspeech/recognition/energy_endpointer.cc
 dom/media/webspeech/recognition/energy_endpointer.h
 dom/media/webspeech/recognition/energy_endpointer_params.cc
 dom/media/webspeech/recognition/energy_endpointer_params.h
+dom/webauthn/cbor-cpp/.*
 dom/webauthn/winwebauthn/webauthn.h
 editor/libeditor/tests/browserscope/lib/richtext/.*
 editor/libeditor/tests/browserscope/lib/richtext2/.*
diff --git a/dom/webauthn/cbor-cpp/src/cbor.h b/dom/webauthn/cbor-cpp/src/cbor.h
index f7db80ffbb22..d0725d166d0b 100644
--- a/dom/webauthn/cbor-cpp/src/cbor.h
+++ b/dom/webauthn/cbor-cpp/src/cbor.h
@@ -7,11 +7,11 @@
 
        http://www.apache.org/licenses/LICENSE-2.0
 
-           Unless required by applicable law or agreed to in writing, software
-           distributed under the License is distributed on an "AS IS" BASIS,
-           WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-   implied. See the License for the specific language governing permissions and
-           limitations under the License.
+	   Unless required by applicable law or agreed to in writing, software
+	   distributed under the License is distributed on an "AS IS" BASIS,
+	   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+	   See the License for the specific language governing permissions and
+	   limitations under the License.
 */
 
 #ifndef CBOR_CPP_CBOR_H
@@ -20,4 +20,4 @@
 #include "encoder.h"
 #include "output_dynamic.h"
 
-#endif  // CBOR_CPP_CBOR_H
+#endif //CBOR_CPP_CBOR_H
diff --git a/dom/webauthn/cbor-cpp/src/encoder.cpp b/dom/webauthn/cbor-cpp/src/encoder.cpp
index cec73f725bfd..ceac69646866 100644
--- a/dom/webauthn/cbor-cpp/src/encoder.cpp
+++ b/dom/webauthn/cbor-cpp/src/encoder.cpp
@@ -7,126 +7,144 @@
 
        http://www.apache.org/licenses/LICENSE-2.0
 
-           Unless required by applicable law or agreed to in writing, software
-           distributed under the License is distributed on an "AS IS" BASIS,
-           WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-   implied. See the License for the specific language governing permissions and
-           limitations under the License.
+	   Unless required by applicable law or agreed to in writing, software
+	   distributed under the License is distributed on an "AS IS" BASIS,
+	   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+	   See the License for the specific language governing permissions and
+	   limitations under the License.
 */
 
 #include "encoder.h"
 
 using namespace cbor;
 
-encoder::encoder(output &out) { _out = &out; }
 
-encoder::~encoder() {}
+encoder::encoder(output &out) {
+    _out = &out;
+}
+
+encoder::~encoder() {
+
+}
 
 void encoder::write_type_value(int major_type, unsigned int value) {
-  major_type <<= 5;
-  if (value < 24) {
-    _out->put_byte((unsigned char)(major_type | value));
-  } else if (value < 256) {
-    _out->put_byte((unsigned char)(major_type | 24));
-    _out->put_byte((unsigned char)value);
-  } else if (value < 65536) {
-    _out->put_byte((unsigned char)(major_type | 25));
-    _out->put_byte((unsigned char)(value >> 8));
-    _out->put_byte((unsigned char)value);
-  } else {
-    _out->put_byte((unsigned char)(major_type | 26));
-    _out->put_byte((unsigned char)(value >> 24));
-    _out->put_byte((unsigned char)(value >> 16));
-    _out->put_byte((unsigned char)(value >> 8));
-    _out->put_byte((unsigned char)value);
-  }
+    major_type <<= 5;
+    if(value < 24) {
+        _out->put_byte((unsigned char) (major_type | value));
+    } else if(value < 256) {
+        _out->put_byte((unsigned char) (major_type | 24));
+        _out->put_byte((unsigned char) value);
+    } else if(value < 65536) {
+        _out->put_byte((unsigned char) (major_type | 25));
+        _out->put_byte((unsigned char) (value >> 8));
+        _out->put_byte((unsigned char) value);
+    } else {
+        _out->put_byte((unsigned char) (major_type | 26));
+        _out->put_byte((unsigned char) (value >> 24));
+        _out->put_byte((unsigned char) (value >> 16));
+        _out->put_byte((unsigned char) (value >> 8));
+        _out->put_byte((unsigned char) value);
+    }
 }
 
 void encoder::write_type_value(int major_type, unsigned long long value) {
-  major_type <<= 5;
-  if (value < 24ULL) {
-    _out->put_byte((unsigned char)(major_type | value));
-  } else if (value < 256ULL) {
-    _out->put_byte((unsigned char)(major_type | 24));
-    _out->put_byte((unsigned char)value);
-  } else if (value < 65536ULL) {
-    _out->put_byte((unsigned char)(major_type | 25));
-    _out->put_byte((unsigned char)(value >> 8));
-    _out->put_byte((unsigned char)value);
-  } else if (value < 4294967296ULL) {
-    _out->put_byte((unsigned char)(major_type | 26));
-    _out->put_byte((unsigned char)(value >> 24));
-    _out->put_byte((unsigned char)(value >> 16));
-    _out->put_byte((unsigned char)(value >> 8));
-    _out->put_byte((unsigned char)value);
-  } else {
-    _out->put_byte((unsigned char)(major_type | 27));
-    _out->put_byte((unsigned char)(value >> 56));
-    _out->put_byte((unsigned char)(value >> 48));
-    _out->put_byte((unsigned char)(value >> 40));
-    _out->put_byte((unsigned char)(value >> 32));
-    _out->put_byte((unsigned char)(value >> 24));
-    _out->put_byte((unsigned char)(value >> 16));
-    _out->put_byte((unsigned char)(value >> 8));
-    _out->put_byte((unsigned char)value);
-  }
+    major_type <<= 5;
+    if(value < 24ULL) {
+        _out->put_byte((unsigned char) (major_type | value));
+    } else if(value < 256ULL) {
+        _out->put_byte((unsigned char) (major_type | 24));
+        _out->put_byte((unsigned char) value);
+    } else if(value < 65536ULL) {
+        _out->put_byte((unsigned char) (major_type | 25));
+        _out->put_byte((unsigned char) (value >> 8));
+        _out->put_byte((unsigned char) value);
+    } else if(value < 4294967296ULL) {
+        _out->put_byte((unsigned char) (major_type | 26));
+        _out->put_byte((unsigned char) (value >> 24));
+        _out->put_byte((unsigned char) (value >> 16));
+        _out->put_byte((unsigned char) (value >> 8));
+        _out->put_byte((unsigned char) value);
+    } else {
+        _out->put_byte((unsigned char) (major_type | 27));
+        _out->put_byte((unsigned char) (value >> 56));
+        _out->put_byte((unsigned char) (value >> 48));
+        _out->put_byte((unsigned char) (value >> 40));
+        _out->put_byte((unsigned char) (value >> 32));
+        _out->put_byte((unsigned char) (value >> 24));
+        _out->put_byte((unsigned char) (value >> 16));
+        _out->put_byte((unsigned char) (value >> 8));
+        _out->put_byte((unsigned char) value);
+    }
 }
 
-void encoder::write_int(unsigned int value) { write_type_value(0, value); }
+void encoder::write_int(unsigned int value) {
+    write_type_value(0, value);
+}
 
 void encoder::write_int(unsigned long long value) {
-  write_type_value(0, value);
+    write_type_value(0, value);
 }
 
 void encoder::write_int(long long value) {
-  if (value < 0) {
-    write_type_value(1, (unsigned long long)-(value + 1));
-  } else {
-    write_type_value(0, (unsigned long long)value);
-  }
+    if(value < 0) {
+        write_type_value(1, (unsigned long long) -(value+1));
+    } else {
+        write_type_value(0, (unsigned long long) value);
+    }
 }
 
 void encoder::write_int(int value) {
-  if (value < 0) {
-    write_type_value(1, (unsigned int)-(value + 1));
-  } else {
-    write_type_value(0, (unsigned int)value);
-  }
+    if(value < 0) {
+        write_type_value(1, (unsigned int) -(value+1));
+    } else {
+        write_type_value(0, (unsigned int) value);
+    }
 }
 
 void encoder::write_bytes(const unsigned char *data, unsigned int size) {
-  write_type_value(2, size);
-  _out->put_bytes(data, size);
+    write_type_value(2, size);
+    _out->put_bytes(data, size);
 }
 
 void encoder::write_string(const char *data, unsigned int size) {
-  write_type_value(3, size);
-  _out->put_bytes((const unsigned char *)data, size);
+    write_type_value(3, size);
+    _out->put_bytes((const unsigned char *) data, size);
 }
 
 void encoder::write_string(const std::string str) {
-  write_type_value(3, (unsigned int)str.size());
-  _out->put_bytes((const unsigned char *)str.c_str(), (int)str.size());
+    write_type_value(3, (unsigned int) str.size());
+    _out->put_bytes((const unsigned char *) str.c_str(), (int) str.size());
 }
 
-void encoder::write_array(int size) { write_type_value(4, (unsigned int)size); }
 
-void encoder::write_map(int size) { write_type_value(5, (unsigned int)size); }
+void encoder::write_array(int size) {
+    write_type_value(4, (unsigned int) size);
+}
 
-void encoder::write_tag(const unsigned int tag) { write_type_value(6, tag); }
+void encoder::write_map(int size) {
+    write_type_value(5, (unsigned int) size);
+}
+
+void encoder::write_tag(const unsigned int tag) {
+    write_type_value(6, tag);
+}
 
 void encoder::write_special(int special) {
-  write_type_value(7, (unsigned int)special);
+    write_type_value(7, (unsigned int) special);
 }
 
 void encoder::write_bool(bool value) {
-  if (value == true) {
-    _out->put_byte((unsigned char)0xf5);
-  } else {
-    _out->put_byte((unsigned char)0xf4);
-  }
+    if (value == true) {
+        _out->put_byte((unsigned char) 0xf5);
+    } else {
+        _out->put_byte((unsigned char) 0xf4);
+    }
 }
 
-void encoder::write_null() { _out->put_byte((unsigned char)0xf6); }
+void encoder::write_null() {
+    _out->put_byte((unsigned char) 0xf6);
+}
 
-void encoder::write_undefined() { _out->put_byte((unsigned char)0xf7); }
\ No newline at end of file
+void encoder::write_undefined() {
+    _out->put_byte((unsigned char) 0xf7);
+}
\ No newline at end of file
diff --git a/dom/webauthn/cbor-cpp/src/encoder.h b/dom/webauthn/cbor-cpp/src/encoder.h
index 80930aa86098..04374b5ed1bd 100644
--- a/dom/webauthn/cbor-cpp/src/encoder.h
+++ b/dom/webauthn/cbor-cpp/src/encoder.h
@@ -7,13 +7,14 @@
 
        http://www.apache.org/licenses/LICENSE-2.0
 
-           Unless required by applicable law or agreed to in writing, software
-           distributed under the License is distributed on an "AS IS" BASIS,
-           WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-   implied. See the License for the specific language governing permissions and
-           limitations under the License.
+	   Unless required by applicable law or agreed to in writing, software
+	   distributed under the License is distributed on an "AS IS" BASIS,
+	   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+	   See the License for the specific language governing permissions and
+	   limitations under the License.
 */
 
+
 #ifndef __CborEncoder_H_
 #define __CborEncoder_H_
 
@@ -21,48 +22,47 @@
 #include <string>
 
 namespace cbor {
-class encoder {
- private:
-  output *_out;
+    class encoder {
+    private:
+        output *_out;
+    public:
+        explicit encoder(output &out);
 
- public:
-  explicit encoder(output &out);
+        ~encoder();
 
-  ~encoder();
+        void write_bool(bool value);
 
-  void write_bool(bool value);
+        void write_int(int value);
 
-  void write_int(int value);
+        void write_int(long long value);
 
-  void write_int(long long value);
+        void write_int(unsigned int value);
 
-  void write_int(unsigned int value);
+        void write_int(unsigned long long value);
 
-  void write_int(unsigned long long value);
+        void write_bytes(const unsigned char *data, unsigned int size);
 
-  void write_bytes(const unsigned char *data, unsigned int size);
+        void write_string(const char *data, unsigned int size);
 
-  void write_string(const char *data, unsigned int size);
+        void write_string(const std::string str);
 
-  void write_string(const std::string str);
+        void write_array(int size);
 
-  void write_array(int size);
+        void write_map(int size);
 
-  void write_map(int size);
+        void write_tag(const unsigned int tag);
 
-  void write_tag(const unsigned int tag);
+        void write_special(int special);
 
-  void write_special(int special);
+        void write_null();
 
-  void write_null();
+        void write_undefined();
 
-  void write_undefined();
+    private:
+        void write_type_value(int major_type, unsigned int value);
 
- private:
-  void write_type_value(int major_type, unsigned int value);
+        void write_type_value(int major_type, unsigned long long value);
+    };
+}
 
-  void write_type_value(int major_type, unsigned long long value);
-};
-}  // namespace cbor
-
-#endif  //__CborEncoder_H_
+#endif //__CborEncoder_H_
diff --git a/dom/webauthn/cbor-cpp/src/output.h b/dom/webauthn/cbor-cpp/src/output.h
index 442e74b3b878..0901d956eb2c 100644
--- a/dom/webauthn/cbor-cpp/src/output.h
+++ b/dom/webauthn/cbor-cpp/src/output.h
@@ -7,27 +7,28 @@
 
        http://www.apache.org/licenses/LICENSE-2.0
 
-           Unless required by applicable law or agreed to in writing, software
-           distributed under the License is distributed on an "AS IS" BASIS,
-           WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-   implied. See the License for the specific language governing permissions and
-           limitations under the License.
+	   Unless required by applicable law or agreed to in writing, software
+	   distributed under the License is distributed on an "AS IS" BASIS,
+	   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+	   See the License for the specific language governing permissions and
+	   limitations under the License.
 */
 
+
 #ifndef __CborOutput_H_
 #define __CborOutput_H_
 
 namespace cbor {
-class output {
- public:
-  virtual unsigned char *data() = 0;
+    class output {
+    public:
+        virtual unsigned char *data() = 0;
 
-  virtual unsigned int size() = 0;
+        virtual unsigned int size() = 0;
 
-  virtual void put_byte(unsigned char value) = 0;
+        virtual void put_byte(unsigned char value) = 0;
 
-  virtual void put_bytes(const unsigned char *data, int size) = 0;
-};
-}  // namespace cbor
+        virtual void put_bytes(const unsigned char *data, int size) = 0;
+    };
+}
 
-#endif  //__CborOutput_H_
+#endif //__CborOutput_H_
diff --git a/dom/webauthn/cbor-cpp/src/output_dynamic.cpp b/dom/webauthn/cbor-cpp/src/output_dynamic.cpp
index 620203197d2c..a9cf46811260 100644
--- a/dom/webauthn/cbor-cpp/src/output_dynamic.cpp
+++ b/dom/webauthn/cbor-cpp/src/output_dynamic.cpp
@@ -7,11 +7,11 @@
 
        http://www.apache.org/licenses/LICENSE-2.0
 
-           Unless required by applicable law or agreed to in writing, software
-           distributed under the License is distributed on an "AS IS" BASIS,
-           WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-   implied. See the License for the specific language governing permissions and
-           limitations under the License.
+	   Unless required by applicable law or agreed to in writing, software
+	   distributed under the License is distributed on an "AS IS" BASIS,
+	   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+	   See the License for the specific language governing permissions and
+	   limitations under the License.
 */
 
 #include "output_dynamic.h"
@@ -21,40 +21,49 @@
 
 using namespace cbor;
 
+
 void output_dynamic::init(unsigned int initalCapacity) {
-  this->_capacity = initalCapacity;
-  this->_buffer = new unsigned char[initalCapacity];
-  this->_offset = 0;
+    this->_capacity = initalCapacity;
+    this->_buffer = new unsigned char[initalCapacity];
+    this->_offset = 0;
 }
 
-output_dynamic::output_dynamic() { init(256); }
+output_dynamic::output_dynamic() {
+    init(256);
+}
 
 output_dynamic::output_dynamic(unsigned int inital_capacity) {
-  init(inital_capacity);
+    init(inital_capacity);
 }
 
-output_dynamic::~output_dynamic() { delete _buffer; }
+output_dynamic::~output_dynamic() {
+    delete _buffer;
+}
 
-unsigned char *output_dynamic::data() { return _buffer; }
+unsigned char *output_dynamic::data() {
+    return _buffer;
+}
 
-unsigned int output_dynamic::size() { return _offset; }
+unsigned int output_dynamic::size() {
+    return _offset;
+}
 
 void output_dynamic::put_byte(unsigned char value) {
-  if (_offset < _capacity) {
-    _buffer[_offset++] = value;
-  } else {
-    _capacity *= 2;
-    _buffer = (unsigned char *)realloc(_buffer, _capacity);
-    _buffer[_offset++] = value;
-  }
+    if(_offset < _capacity) {
+        _buffer[_offset++] = value;
+    } else {
+        _capacity *= 2;
+        _buffer = (unsigned char *) realloc(_buffer, _capacity);
+        _buffer[_offset++] = value;
+    }
 }
 
 void output_dynamic::put_bytes(const unsigned char *data, int size) {
-  while (_offset + size > _capacity) {
-    _capacity *= 2;
-    _buffer = (unsigned char *)realloc(_buffer, _capacity);
-  }
+    while(_offset + size > _capacity) {
+        _capacity *= 2;
+        _buffer = (unsigned char *) realloc(_buffer, _capacity);
+    }
 
-  memcpy(_buffer + _offset, data, size);
-  _offset += size;
+    memcpy(_buffer + _offset, data, size);
+    _offset += size;
 }
diff --git a/dom/webauthn/cbor-cpp/src/output_dynamic.h b/dom/webauthn/cbor-cpp/src/output_dynamic.h
index 91e682cf58eb..d6c7e460ce5c 100644
--- a/dom/webauthn/cbor-cpp/src/output_dynamic.h
+++ b/dom/webauthn/cbor-cpp/src/output_dynamic.h
@@ -7,43 +7,45 @@
 
        http://www.apache.org/licenses/LICENSE-2.0
 
-           Unless required by applicable law or agreed to in writing, software
-           distributed under the License is distributed on an "AS IS" BASIS,
-           WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-   implied. See the License for the specific language governing permissions and
-           limitations under the License.
+	   Unless required by applicable law or agreed to in writing, software
+	   distributed under the License is distributed on an "AS IS" BASIS,
+	   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+	   See the License for the specific language governing permissions and
+	   limitations under the License.
 */
 
 #ifndef __CborDynamicOutput_H_
 #define __CborDynamicOutput_H_
 
+
 #include "output.h"
 
 namespace cbor {
-class output_dynamic : public output {
- private:
-  unsigned char *_buffer;
-  unsigned int _capacity;
-  unsigned int _offset;
+    class output_dynamic : public output {
+    private:
+        unsigned char *_buffer;
+        unsigned int _capacity;
+        unsigned int _offset;
+    public:
+        output_dynamic();
 
- public:
-  output_dynamic();
+        explicit output_dynamic(unsigned int inital_capacity);
 
-  explicit output_dynamic(unsigned int inital_capacity);
+        ~output_dynamic();
 
-  ~output_dynamic();
+        virtual unsigned char *data();
 
-  virtual unsigned char *data();
+        virtual unsigned int size();
 
-  virtual unsigned int size();
+        virtual void put_byte(unsigned char value);
 
-  virtual void put_byte(unsigned char value);
+        virtual void put_bytes(const unsigned char *data, int size);
 
-  virtual void put_bytes(const unsigned char *data, int size);
+    private:
+        void init(unsigned int initalCapacity);
+    };
+}
 
- private:
-  void init(unsigned int initalCapacity);
-};
-}  // namespace cbor
 
-#endif  //__CborDynamicOutput_H_
+
+#endif //__CborDynamicOutput_H_
diff --git a/gfx/layers/apz/test/mochitest/test_group_minimum_scale_size.html b/gfx/layers/apz/test/mochitest/test_group_minimum_scale_size.html
index 8db9c1d195d8..bc502d91c670 100644
--- a/gfx/layers/apz/test/mochitest/test_group_minimum_scale_size.html
+++ b/gfx/layers/apz/test/mochitest/test_group_minimum_scale_size.html
@@ -30,13 +30,6 @@ const prefs = [
   // Pinch-zooming currently requires meta viewport support (this requirement
   // will eventually be removed).
   ["dom.meta-viewport.enabled", true],
-  // Pinch-zooming currently requires container scrolling (this requirement
-  // will eventually be removed).
-  ["layout.scroll.root-frame-containers", 1],
-  // Retained displaylists don't work well with container scrolling, so
-  // they too need to be disabled for now.
-  ["layout.display-list.retain", false],
-  ["layout.display-list.retain.chrome", false],
   // We use the Visual Viewport API to tell the visual viewport offset.
   ["dom.visualviewport.enabled", true],
 ];
diff --git a/gfx/layers/apz/test/mochitest/test_group_zoom.html b/gfx/layers/apz/test/mochitest/test_group_zoom.html
index 75f54991e27b..d07391bcbf75 100644
--- a/gfx/layers/apz/test/mochitest/test_group_zoom.html
+++ b/gfx/layers/apz/test/mochitest/test_group_zoom.html
@@ -32,10 +32,6 @@ var prefs = [
   // Pinch-zooming currently requires meta viewport support (this requirement
   // will eventually be removed).
   ["dom.meta-viewport.enabled", true],
-  // Retained displaylists don't work well with container scrolling, so
-  // they too need to be disabled for now.
-  ["layout.display-list.retain", false],
-  ["layout.display-list.retain.chrome", false],
 ];
 
 // Increase the tap timeouts so the double-tap is still detected in case of
diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
index 87ffe1c7fba7..ceff186a8f55 100644
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -1376,6 +1376,20 @@ void nsBlockFrame::Reflow(nsPresContext* aPresContext, ReflowOutput& aMetrics,
       } else {
         absoluteContainer->MarkSizeDependentFramesDirty();
       }
+      if (haveInterrupt) {
+        // We're not going to reflow absolute frames; make sure to account for
+        // their existing overflow areas, which is usually a side effect of this
+        // reflow.
+        //
+        // TODO(emilio): nsAbsoluteContainingBlock::Reflow already checks for
+        // interrupt, can we just rely on it and unconditionally take the else
+        // branch below? That's a bit more subtle / risky, since I don't see
+        // what would reflow them in that case if they depended on our size.
+        for (nsIFrame* kid = absoluteContainer->GetChildList().FirstChild(); kid;
+             kid = kid->GetNextSibling()) {
+          ConsiderChildOverflow(aMetrics.mOverflowAreas, kid);
+        }
+      }
     } else {
       LogicalSize containingBlockSize =
           CalculateContainingBlockSizeForAbsolutes(parentWM, *reflowInput,
diff --git a/layout/generic/nsGfxScrollFrame.cpp b/layout/generic/nsGfxScrollFrame.cpp
index 0353f6b11baa..ff52ae984645 100644
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -3893,10 +3893,9 @@ bool ScrollFrameHelper::DecideScrollableLayer(
     aBuilder->RecomputeCurrentAnimatedGeometryRoot();
   }
 
-  if (gfxPrefs::LayoutUseContainersForRootFrames() &&
-      mWillBuildScrollableLayer && mIsRoot) {
-    mIsScrollableLayerInRootContainer = true;
-  }
+  mIsScrollableLayerInRootContainer =
+      gfxPrefs::LayoutUseContainersForRootFrames() &&
+      mWillBuildScrollableLayer && mIsRoot;
   return mWillBuildScrollableLayer;
 }
 
diff --git a/layout/generic/test/mochitest.ini b/layout/generic/test/mochitest.ini
index 0db8e36f599e..e500d02d1f4c 100644
--- a/layout/generic/test/mochitest.ini
+++ b/layout/generic/test/mochitest.ini
@@ -132,6 +132,7 @@ skip-if = toolkit == 'android' || headless # Headless:Bug 1405871
 [test_plugin_position.xhtml]
 skip-if = e10s
 [test_scroll_behavior.html]
+[test_scrollframe_abspos_interrupt.html]
 [test_selection_expanding.html]
 support-files = selection_expanding_xbl.xml
 [test_selection_preventDefault.html]
diff --git a/layout/generic/test/test_scrollframe_abspos_interrupt.html b/layout/generic/test/test_scrollframe_abspos_interrupt.html
new file mode 100644
index 000000000000..fe25e991f941
--- /dev/null
+++ b/layout/generic/test/test_scrollframe_abspos_interrupt.html
@@ -0,0 +1,60 @@
+<!doctype html>
+<title>Test for bug 1526609</title>
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<script src="/tests/SimpleTest/EventUtils.js"></script>
+<style>
+  body {
+    margin: 0;
+  }
+  .scroller {
+    overflow-y: auto;
+    position: relative;
+    width: 500px;
+    height: 300px;
+  }
+  .kid {
+    position: absolute;
+    width: 100%;
+    background: linear-gradient(to bottom, red, green);
+    line-height: 100px;
+  }
+</style>
+<div class="scroller" id="scroller">
+  <div class="kid"></div>
+</div>
+<script>
+{
+  let text = " foo bar ";
+
+  for (let i = 0; i < 16; ++i)
+    text = text + text;
+  document.querySelector(".kid").innerText = text;
+}
+
+SimpleTest.waitForExplicitFinish();
+
+const scroller = document.querySelector("#scroller");
+
+is(scroller.scrollTop, 0, "Initial scroll position");
+ok(scroller.scrollTopMax > 0, "Should be able to scroll down");
+
+scroller.scrollTop = scroller.scrollTopMax;
+is(scroller.scrollTop, scroller.scrollTopMax, "Should've scrolled");
+
+const origWidth = scroller.offsetWidth;
+const utils = SpecialPowers.DOMWindowUtils;
+
+// Take control of the refresh driver
+utils.advanceTimeAndRefresh(0);
+
+// Force the next reflow to get interrupted
+utils.forceReflowInterrupt();
+scroller.style.width = "300px";
+utils.advanceTimeAndRefresh(0);
+
+isnot(scroller.scrollTop, 0, "Shouldn't have lost scroll position");
+isnot(scroller.offsetWidth, origWidth, "Should've had to reflow");
+
+utils.restoreNormalRefresh();
+SimpleTest.finish();
+</script>
diff --git a/layout/reftests/meta-viewport/position-fixed-out-of-view.html b/layout/reftests/meta-viewport/position-fixed-out-of-view.html
index 5823b7248148..02d889d0c827 100644
--- a/layout/reftests/meta-viewport/position-fixed-out-of-view.html
+++ b/layout/reftests/meta-viewport/position-fixed-out-of-view.html
@@ -13,4 +13,4 @@
   it should not be visible in the initial viewport position(0,0).
 -->
 <div style="position:fixed; top:0; right: 0; width:100px; height: 100px; background-color: green"></div>
-<div style="width: 200%; height: 100%;"></div>
+<div style="width: 200%; height: 200%;"></div>
diff --git a/taskcluster/ci/searchfox/kind.yml b/taskcluster/ci/searchfox/kind.yml
index 2af69849d258..cb10148859f0 100644
--- a/taskcluster/ci/searchfox/kind.yml
+++ b/taskcluster/ci/searchfox/kind.yml
@@ -117,3 +117,4 @@ jobs:
             - win64-node
             - win64-rust
             - win64-cbindgen
+            - win64-nasm
diff --git a/toolkit/content/xul.css b/toolkit/content/xul.css
index 2611710186a1..7f1c0d366fc3 100644
--- a/toolkit/content/xul.css
+++ b/toolkit/content/xul.css
@@ -442,8 +442,6 @@ tree > treechildren {
 
 tree {
   -moz-box-orient: vertical;
-  min-width: 0px;
-  min-height: 0px;
   width: 10px;
   height: 10px;
 }
diff --git a/tools/rewriting/ThirdPartyPaths.txt b/tools/rewriting/ThirdPartyPaths.txt
index 8f79b4d1a7cc..3cbe1dc4258f 100644
--- a/tools/rewriting/ThirdPartyPaths.txt
+++ b/tools/rewriting/ThirdPartyPaths.txt
@@ -21,6 +21,7 @@ dom/media/webspeech/recognition/energy_endpointer.cc
 dom/media/webspeech/recognition/energy_endpointer.h
 dom/media/webspeech/recognition/energy_endpointer_params.cc
 dom/media/webspeech/recognition/energy_endpointer_params.h
+dom/webauthn/cbor-cpp/
 editor/libeditor/tests/browserscope/lib/richtext/
 editor/libeditor/tests/browserscope/lib/richtext2/
 extensions/spellcheck/hunspell/src/