Make Blink stop scheduling its own Layout, and use the compositor's timer instead

Source/core/rendering/RenderIFrame.cpp

Index: Source/core/rendering/RenderIFrame.cpp
diff --git a/Source/core/rendering/RenderIFrame.cpp b/Source/core/rendering/RenderIFrame.cpp
index a4b649a2d7b4fd4954834ff58108f0d548bb99ed..83acd5929ce63d0d4d9098b58bb9943bb803a867 100644
--- a/Source/core/rendering/RenderIFrame.cpp
+++ b/Source/core/rendering/RenderIFrame.cpp
@@ -115,7 +115,7 @@ void RenderIFrame::layoutSeamlessly()
 
     // Assert that the child document did a complete layout.
     RenderView* childRoot = childFrameView ? childFrameView->frame()->contentRenderer() : 0;
-    ASSERT(!childFrameView || !childFrameView->layoutPending());
+    ASSERT(!childFrameView || !childFrameView->layoutIsScheduledWithEmbedder());
     ASSERT_UNUSED(childRoot, !childRoot || !childRoot->needsLayout());
 }