Fixed clip resize for document.rootScroller with inertTopControls

third_party/WebKit/Source/core/page/scrolling/TopDocumentRootScrollerController.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/page/scrolling/TopDocumentRootScrollerController.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
@@ skipping 23 matching lines @@
 DEFINE_TRACE(TopDocumentRootScrollerController) {
   visitor->trace(m_viewportApplyScroll);
   visitor->trace(m_globalRootScroller);
   visitor->trace(m_frameHost);
 }
 
 void TopDocumentRootScrollerController::didChangeRootScroller() {
   recomputeGlobalRootScroller();
 }
 
+void TopDocumentRootScrollerController::mainFrameViewResized() {
+  Element* rootScroller = globalRootScroller();
+  if (!rootScroller)
+    return;
+
+  ScrollableArea* area = RootScrollerUtil::scrollableAreaFor(*rootScroller);
+
+  if (!area)
+    return;
+
+  if (PaintLayer* layer = area->layer()) {
+    layer->setNeedsCompositingInputsUpdate();

[bokan, 2016/11/15 00:20:09]

This isn't really a CompositingInputsUpdate, but I need to mark the
CompositedLayerMapping as needsGraphicsLayerUpdate and I don't think there's a
way to do that from PaintLayer. We can't query compositing state at this point
so I can't ask for the CLM.

Is there a right way to do this, or is this ok? Or should I just disable the
compositing query asserts?

+
+    // This is needed if the root scroller is an iframe, since the iframe
+    // doesn't have a scrolling/clip layer, its PLC has a container layer that
+    // needs to be resized instead.
+    layer->compositor()->frameViewDidChangeSize();
+  }
+}
+
 Element* TopDocumentRootScrollerController::findGlobalRootScrollerElement() {
   if (!topDocument())
     return nullptr;
 
   DCHECK(topDocument()->rootScrollerController());
   Element* element =
       topDocument()->rootScrollerController()->effectiveRootScroller();
 
   while (element && element->isFrameOwnerElement()) {
     HTMLFrameOwnerElement* frameOwner = toHTMLFrameOwnerElement(element);
@@ skipping 123 matching lines @@
   // the root scroller gets composited.
 
   return graphicsLayer;
 }
 
 Element* TopDocumentRootScrollerController::globalRootScroller() const {
   return m_globalRootScroller.get();
 }
 
 }  // namespace blink