Stop painting when receiving delegated frame

ui/compositor/layer.cc

 // Copyright (c) 2012 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 "ui/compositor/layer.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 672 matching lines @@
   RecomputePosition();
   SchedulePaint(gfx::Rect(bounds_.size()));
   if (delegate_)
     delegate_->OnDeviceScaleFactorChanged(device_scale_factor);
   for (size_t i = 0; i < children_.size(); ++i)
     children_[i]->OnDeviceScaleFactorChanged(device_scale_factor);
   if (layer_mask_)
     layer_mask_->OnDeviceScaleFactorChanged(device_scale_factor);
 }
 
+void Layer::OnDelegatedFrameDamage(const gfx::Rect &damage_rect_in_dip) {

[enne (OOO), 2014/08/21 20:54:19]

piman, danakj: removed DCHECK about having a delegated_renderer_layer_ or
texture_layer_ here.

Unfortunately this outline of code makes that problematic:

DelegatedFrameHost::SwapDelegatedFrame
  if (output_surface_id != last_output_surface_id_)
    DelegatedFrameHost::EvictDelegatedFrame
      Layer::SetShowPaintedContent
        Layer::SwitchToLayer(content or picture layer)
  Layer::OnDelegatedFrameData
    DCHECK(is a delegated renderer layer)
    BOOM

[enne (OOO), 2014/08/22 17:26:04]

danakj (or piman): PTAL?

+  if (!delegate_)
+    return;
+  delegate_->OnDelegatedFrameDamage(damage_rect_in_dip);
+}
+
 void Layer::RequestCopyOfOutput(scoped_ptr<cc::CopyOutputRequest> request) {
   cc_layer_->RequestCopyOfOutput(request.Pass());
 }
 
 void Layer::PaintContents(SkCanvas* sk_canvas,
                           const gfx::Rect& clip,
                           gfx::RectF* opaque,
                           ContentLayerClient::GraphicsContextStatus gc_status) {
   TRACE_EVENT0("ui", "Layer::PaintContents");
   scoped_ptr<gfx::Canvas> canvas(gfx::Canvas::CreateCanvasWithoutScaling(
@@ skipping 325 matching lines @@
       children_.end(),
       std::bind2nd(std::mem_fun(&Layer::RemoveAnimatorsInTreeFromCollection),
                    collection));
 }
 
 bool Layer::IsAnimating() const {
   return animator_ && animator_->is_animating();
 }
 
 }  // namespace ui