Bug 1452225 - Rebuild the whole subdoc when the caret changes, but don't invalidate the nsDisplaySubdocument. r=miko

MozReview-Commit-ID: K0KLXTo4GG

--HG--
extra : rebase_source : 54fc03744cb9df58497ba843fb6786c4db98fb64

layout/generic/nsSubDocumentFrame.cpp

@@ -447,18 +447,6 @@ nsSubDocumentFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
   }
 
   if (aBuilder->IsRetainingDisplayList()) {
-    // The value of needsOwnLayer can change between builds without
-    // an invalidation recorded for this frame (like if the root
-    // scrollframe becomes active). If this happens,
-    // then we need to notify the builder so that merging can
-    // happen correctly.
-    if (!mPreviouslyNeededLayer ||
-        mPreviouslyNeededLayer.value() != needsOwnLayer) {
-      dirty = visible;
-      aBuilder->MarkCurrentFrameModifiedDuringBuilding();
-    }
-    mPreviouslyNeededLayer = Some(needsOwnLayer);
-
     // Caret frame changed, rebuild the entire subdoc.
     // We could just invalidate the old and new frame
     // areas and save some work here. RetainedDisplayListBuilder
@@ -466,7 +454,14 @@ nsSubDocumentFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
     // subdocs in advance.
     if (mPreviousCaret != aBuilder->GetCaretFrame()) {
       dirty = visible;
-      aBuilder->MarkCurrentFrameModifiedDuringBuilding();
+      aBuilder->RebuildAllItemsInCurrentSubtree();
+      // Mark the old caret frame as invalid so that we remove the
+      // old nsDisplayCaret. We don't mark the current frame as invalid
+      // since we want the nsDisplaySubdocument to retain it's place
+      // in the retained display list.
+      if (mPreviousCaret) {
+        aBuilder->MarkFrameModifiedDuringBuilding(mPreviousCaret);
+      }
     }
     mPreviousCaret = aBuilder->GetCaretFrame();
   }

layout/generic/nsSubDocumentFrame.h

@@ -168,7 +168,6 @@ protected:
   RefPtr<nsFrameLoader> mFrameLoader;
   nsView* mOuterView;
   nsView* mInnerView;
-  Maybe<bool> mPreviouslyNeededLayer;
   bool mIsInline;
   bool mPostedReflowCallback;
   bool mDidCreateDoc;

layout/painting/nsDisplayList.h

@@ -1747,6 +1747,12 @@ public:
     return false;
   }
 
+  void RebuildAllItemsInCurrentSubtree()
+  {
+    mInInvalidSubtree = true;
+    mDirtyRect = mVisibleRect;
+  }
+
   /**
    * This is a convenience function to ease the transition until AGRs and ASRs
    * are unified.