Browser side changes for software compositing

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 "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkDevice.h"
@@ skipping 112 matching lines @@
 
   last_buffer_ = front_buffer_;
   front_buffer_ = (front_buffer_ + 1) % dibs_.size();
   --num_free_buffers_;
   DCHECK_GE(num_free_buffers_, 0);
 }
 
 void CompositorSoftwareOutputDevice::ReclaimDIB(const TransportDIB::Id& id) {
   DCHECK(CalledOnValidThread());
 
-  // The reclaimed handle might not be among the currently
+  // The reclaimed dib id might not be among the currently
   // active dibs if we got a resize event in the mean time.
   ScopedVector<TransportDIB>::iterator it =
       std::find_if(dibs_.begin(), dibs_.end(), CompareById(id));
   if (it != dibs_.end()) {
     ++num_free_buffers_;
-  } else {
-    it = std::find_if(awaiting_ack_.begin(),
-                      awaiting_ack_.end(),
-                      CompareById(id));
-    awaiting_ack_.erase(it);
+    DCHECK_LE(static_cast<size_t>(num_free_buffers_), dibs_.size());
+    return;
   }
 
-  DCHECK_LE(static_cast<size_t>(num_free_buffers_), dibs_.size());
+  // Check if this dib id is among awaiting_ack_.
+  it = std::find_if(awaiting_ack_.begin(), awaiting_ack_.end(),
+                    CompareById(id));
+  DCHECK(it != awaiting_ack_.end());
+  if (it != awaiting_ack_.end())

[piman, 2013/04/03 21:54:42]

nit: with the DCHECK, the if is unnecessary, right?

Follow-up: from the changes in RWHVA I see now that there is the case for the
"invalid" returned id for the first frame. This should be handled explicitly I
think, so that a logic error would still trigger the DCHECK.

[piman, 2013/04/05 21:07:29]

ping

+    awaiting_ack_.erase(it);
 }
 
 }  // namespace content