Bug 1622360 - Remove rest of the RenderRootBoundary stuff. r=botond

Depends on D67866

Differential Revision: https://phabricator.services.mozilla.com/D67867

--HG--
extra : moz-landing-system : lando

gfx/layers/moz.build

@@ -258,7 +258,6 @@ EXPORTS.mozilla.layers += [
     'wr/ClipManager.h',
     'wr/DisplayItemCache.h',
     'wr/IpcResourceUpdateQueue.h',
-    'wr/RenderRootBoundary.h',
     'wr/RenderRootStateManager.h',
     'wr/RenderRootTypes.h',
     'wr/StackingContextHelper.h',

gfx/layers/wr/RenderRootBoundary.h

@@ -1,96 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef GFX_RENDERROOTBOUNDARY_H
-#define GFX_RENDERROOTBOUNDARY_H
-
-#include "mozilla/webrender/WebRenderTypes.h"
-
-#include <string>
-#include <sstream>
-
-namespace mozilla {
-namespace layers {
-
-// clang-format off
-// A display list can have multiple nsDisplayRenderRoot instances in it, one
-// at each point that the display list transitions from being in one render root
-// to another. In particular, this means that a display list can transition
-// from e.g. the "Default" render root to the "Content" render root multiple
-// times. When we process this display list in WebRenderCommandBuilder, we build
-// a WebRenderScrollData for each render root, and they are "connected" by the
-// referent render root property on the WebRenderLayerScrollData instances.
-// (This is similar to how the layers id referent property works, i.e. a WRLSD
-// item with a referent is an attachment point for a subtree from a different
-// render root.) But given that there are multiple transitions to the same
-// "child" render root, we need an additional data point to uniquely identify
-// each of the transitions, so that we can attach the correct scroll data
-// subtree at each transition. Failure to uniquely identify the transitions
-// means that the entire "child" render root's scroll data tree will get
-// attached at each transition. The RenderRootBoundary class serves this
-// purpose.
-//
-// Example time! Consider the following display list structure:
-//
-//           R        // root of the display list
-//          / \       //
-//         A   B      // items in Default render root that generate scroll data
-//        /   / \     //
-//       C   D   E    // nsDisplayRenderRoot items transitioning to content
-//      / \     /     //
-//     F   G   H      // items in Content render root that generate scroll data
-//
-// In this example, the Default render root WebRenderScrollData will contain
-// 6 WRLSD items, one for each of R, A, B, C, D, E. Of these, C, D, and E will
-// have mReferentRenderRoot properties set. The WebRenderScrollData for the
-// Content render root will end up looking like this:
-//
-//          Dummy root         //
-//          /        \         //
-//        C-Root    E-Root     //
-//       /    |       |        //
-//      F     G       H        //
-//
-// The RenderRootBoundary item on C will point to C-Root, and likewise for E.
-// The RenderRootBoundary item on D will be valid, but there will be no
-// corresponding subtree in the Content-side WebRenderScrollData. C-Root and
-// E-Root are created via WebRenderScrollDataCollection::AppendWrapper, and
-// have their mBoundaryRoot property set to the same RenderRootBoundary value
-// as the mReferentRenderRoot properties from C and E respectively.
-// clang-format on
-class RenderRootBoundary {
- public:
-  explicit RenderRootBoundary(wr::RenderRoot aChildType)
-      : mChildType(aChildType) {
-    static uint64_t sCounter = 0;
-    mId = ++sCounter;
-  }
-
-  wr::RenderRoot GetChildType() const { return mChildType; }
-
-  bool operator==(const RenderRootBoundary& aOther) const {
-    return mChildType == aOther.mChildType && mId == aOther.mId;
-  }
-
-  friend struct IPC::ParamTraits<RenderRootBoundary>;
-  // constructor for IPC
-  RenderRootBoundary() = default;
-
-  std::string ToString() const {
-    std::stringstream str;
-    str << "childType=" << (int)mChildType << "; id=" << mId;
-    return str.str();
-  }
-
- private:
-  wr::RenderRoot mChildType;
-  // The id is what distinguishes different transition points within a display
-  // list (i.e. what would be different in C, D, and E in the example above).
-  uint64_t mId;
-};
-
-}  // namespace layers
-}  // namespace mozilla
-
-#endif  // GFX_RENDERROOTBOUNDARY_H

gfx/layers/wr/WebRenderCommandBuilder.h

@@ -9,7 +9,6 @@
 
 #include "mozilla/webrender/WebRenderAPI.h"
 #include "mozilla/layers/ClipManager.h"
-#include "mozilla/layers/RenderRootBoundary.h"
 #include "mozilla/layers/WebRenderMessages.h"
 #include "mozilla/layers/WebRenderScrollData.h"
 #include "mozilla/layers/WebRenderUserData.h"

gfx/layers/wr/WebRenderScrollData.h

@@ -18,7 +18,6 @@
 #include "mozilla/layers/LayerAttributes.h"
 #include "mozilla/layers/LayersMessageUtils.h"
 #include "mozilla/layers/FocusTarget.h"
-#include "mozilla/layers/RenderRootBoundary.h"
 #include "mozilla/layers/WebRenderMessageUtils.h"
 #include "mozilla/webrender/WebRenderTypes.h"
 #include "mozilla/HashTable.h"
@@ -97,11 +96,6 @@ class WebRenderLayerScrollData final {
   void SetReferentId(LayersId aReferentId) { mReferentId = Some(aReferentId); }
   Maybe<LayersId> GetReferentId() const { return mReferentId; }
 
-  Maybe<RenderRootBoundary> GetReferentRenderRoot() const {
-    return Nothing();
-  }
-  Maybe<RenderRootBoundary> GetBoundaryRoot() const { return Nothing(); }
-
   void SetScrollbarData(const ScrollbarData& aData) { mScrollbarData = aData; }
   const ScrollbarData& GetScrollbarData() const { return mScrollbarData; }
   void SetScrollbarAnimationId(const uint64_t& aId) {
@@ -261,10 +255,6 @@ class WebRenderScrollData final {
 
 namespace IPC {
 
-template <>
-struct ParamTraits<mozilla::layers::RenderRootBoundary>
-    : public PlainOldDataSerializer<mozilla::layers::RenderRootBoundary> {};
-
 template <>
 struct ParamTraits<mozilla::layers::WebRenderLayerScrollData> {
   typedef mozilla::layers::WebRenderLayerScrollData paramType;

gfx/layers/wr/WebRenderScrollDataWrapper.h

@@ -158,44 +158,6 @@ class MOZ_STACK_CLASS WebRenderScrollDataWrapper final {
                                         mLayerIndex + 1, subtreeLastIndex);
     }
 
-    if (mLayer->GetReferentRenderRoot()) {
-      MOZ_ASSERT(!mLayer->GetReferentId());
-      MOZ_ASSERT(mLayer->GetReferentRenderRoot()->GetChildType() !=
-                 mWrRootId.mRenderRoot);
-
-      WRRootId newWrRootId = WRRootId(
-          mWrRootId.mLayersId, mLayer->GetReferentRenderRoot()->GetChildType());
-      const WebRenderScrollData* childData =
-          mUpdater->GetScrollData(newWrRootId);
-      if (!childData) {
-        // The other tree might not exist yet if the scene hasn't been built.
-        return WebRenderScrollDataWrapper(*mUpdater, newWrRootId);
-      }
-      // See the comment above RenderRootBoundary for more context on what's
-      // happening here. We need to fish out the appropriate wrapper root from
-      // inside the dummy root. Note that the wrapper root should always be a
-      // direct descendant of the dummy root, so we can pass
-      // `childData->GetLayerCount()` for the `aContainingSubtreeLastIndex`
-      // parameter below.
-      Maybe<size_t> layerIndex;
-      for (size_t i = 0; i < childData->GetLayerCount(); i++) {
-        const WebRenderLayerScrollData* wrlsd = childData->GetLayerData(i);
-        if (wrlsd->GetBoundaryRoot() == mLayer->GetReferentRenderRoot()) {
-          // found it
-          layerIndex = Some(i);
-          break;
-        }
-      }
-      if (!layerIndex) {
-        // It's possible that there's no wrapper root. In that case there are
-        // no descendants
-        return WebRenderScrollDataWrapper(*mUpdater, newWrRootId);
-      }
-      return WebRenderScrollDataWrapper(mUpdater, newWrRootId, childData,
-                                        *layerIndex,
-                                        childData->GetLayerCount());
-    }
-
     // We've run out of descendants. But! If the original layer was a RefLayer,
     // then it connects to another layer tree and we need to traverse that too.
     // So return a WebRenderScrollDataWrapper for the root of the child layer
@@ -326,11 +288,6 @@ class MOZ_STACK_CLASS WebRenderScrollDataWrapper final {
   Maybe<wr::RenderRoot> GetReferentRenderRoot() const {
     MOZ_ASSERT(IsValid());
 
-    if (AtBottomLayer()) {
-      if (mLayer->GetReferentRenderRoot()) {
-        return Some(mLayer->GetReferentRenderRoot()->GetChildType());
-      }
-    }
     return Nothing();
   }
 

gfx/layers/wr/WebRenderUserData.h

@@ -12,7 +12,6 @@
 #include "mozilla/layers/StackingContextHelper.h"
 #include "mozilla/webrender/WebRenderAPI.h"
 #include "mozilla/layers/AnimationInfo.h"
-#include "mozilla/layers/RenderRootBoundary.h"
 #include "mozilla/dom/RemoteBrowser.h"
 #include "mozilla/UniquePtr.h"
 #include "nsIFrame.h"

layout/painting/nsDisplayList.h

@@ -43,7 +43,6 @@
 #include "mozilla/TimeStamp.h"
 #include "mozilla/gfx/UserData.h"
 #include "mozilla/layers/LayerAttributes.h"
-#include "mozilla/layers/RenderRootBoundary.h"
 #include "mozilla/layers/ScrollableLayerGuid.h"
 #include "nsCSSRenderingBorders.h"
 #include "nsPresArena.h"