Start out deferring commits in WebViewImpl

third_party/WebKit/Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 3980 matching lines @@
     if (layer_tree_view_ && layer_tree_view_->CompositorAnimationHost()) {
       animation_host_ = WTF::MakeUnique<CompositorAnimationHost>(
           layer_tree_view_->CompositorAnimationHost());
     }
   }
 
   if (WebDevToolsAgentImpl* dev_tools = MainFrameDevToolsAgentImpl())
     dev_tools->LayerTreeViewChanged(layer_tree_view_);
 
   page_->GetSettings().SetAcceleratedCompositingEnabled(layer_tree_view_);
-  if (layer_tree_view_)
+  if (layer_tree_view_) {
     page_->LayerTreeViewInitialized(*layer_tree_view_, nullptr);
+    // We don't yet have a page loaded at this point of the initialization of
+    // WebViewImpl, so don't allow cc to commit any frames Blink might
+    // try to create in the meantime.
+    layer_tree_view_->SetDeferCommits(true);
+  }
 
   // FIXME: only unittests, click to play, Android printing, and printing (for
   // headers and footers) make this assert necessary. We should make them not
   // hit this code and then delete allowsBrokenNullLayerTreeView.
   DCHECK(layer_tree_view_ || !client_ ||
          client_->WidgetClient()->AllowsBrokenNullLayerTreeView());
 
   if (Platform::Current()->IsThreadedAnimationEnabled() && layer_tree_view_) {
     link_highlights_timeline_ = CompositorAnimationTimeline::Create();
     AttachCompositorAnimationTimeline(link_highlights_timeline_.get());
@@ skipping 167 matching lines @@
   if (focused_frame->LocalFrameRoot() != MainFrameImpl()->GetFrame())
     return nullptr;
   return focused_frame;
 }
 
 LocalFrame* WebViewImpl::FocusedLocalFrameAvailableForIme() const {
   return ime_accept_events_ ? FocusedLocalFrameInWidget() : nullptr;
 }
 
 }  // namespace blink