Re-land: cc: Cancel and re-prioritize worker pool tasks.

cc/resources/resource_provider.cc

 // Copyright 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 "cc/resources/resource_provider.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/debug/alias.h"
@@ skipping 950 matching lines @@
     WebGraphicsContext3D* context3d = output_surface_->context3d();
     DCHECK(context3d);
     DCHECK(resource->gl_pixel_buffer_id);
     context3d->bindBuffer(
         GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM,
         resource->gl_pixel_buffer_id);
     uint8_t* image = static_cast<uint8_t*>(
         context3d->mapBufferCHROMIUM(
             GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM, GL_WRITE_ONLY));
     context3d->bindBuffer(GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM, 0);
+    // Buffer is required to be 4-byte aligned.
+    CHECK(!(reinterpret_cast<intptr_t>(image) & 3));
     return image;
   }
 
   if (resource->pixels)
     return resource->pixel_buffer;
 
   return NULL;
 }
 
 void ResourceProvider::UnmapPixelBuffer(ResourceId id) {
@@ skipping 255 matching lines @@
 void ResourceProvider::EnableReadLockFences(ResourceProvider::ResourceId id,
                                             bool enable) {
   DCHECK(thread_checker_.CalledOnValidThread());
   ResourceMap::iterator it = resources_.find(id);
   CHECK(it != resources_.end());
   Resource* resource = &it->second;
   resource->enable_read_lock_fences = enable;
 }
 
 }  // namespace cc