Add debugging info for software compositor swap.

content/renderer/gpu/compositor_software_output_device.cc

 // Copyright (c) 2013 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 "content/renderer/gpu/compositor_software_output_device.h"
 
 #include "base/logging.h"
 #include "cc/output/software_frame_data.h"
 #include "content/renderer/render_process.h"
 #include "third_party/skia/include/core/SkBitmapDevice.h"
@@ skipping 183 matching lines @@
 void CompositorSoftwareOutputDevice::EndPaint(
     cc::SoftwareFrameData* frame_data) {
   DCHECK(CalledOnValidThread());
   DCHECK(frame_data);
 
   Buffer* buffer = buffers_[current_index_];
   frame_data->id = buffer->id();
   frame_data->size = viewport_size_;
   frame_data->damage_rect = damage_rect_;
   frame_data->handle = buffer->handle();
+
+  CHECK_LE(static_cast<size_t>(frame_data->size.GetArea()) * 4,
+           buffer->shared_memory()->mapped_size());
 }
 
 void CompositorSoftwareOutputDevice::ReclaimSoftwareFrame(unsigned id) {
   DCHECK(CalledOnValidThread());
 
   if (!id)
     return;
 
   // The reclaimed buffer id might not be among the currently
   // active buffers if we got a resize event in the mean time.
   ScopedVector<Buffer>::iterator it =
       std::find_if(buffers_.begin(), buffers_.end(), CompareById(id));
   if (it != buffers_.end()) {
     DCHECK(!(*it)->free());
     (*it)->SetFree(true);
     return;
   } else {
     it = std::find_if(awaiting_ack_.begin(), awaiting_ack_.end(),
                       CompareById(id));
     DCHECK(it != awaiting_ack_.end());
     awaiting_ack_.erase(it);
   }
 }
 
 }  // namespace content