Add compositor support for half-float RGBA buffers and textures

cc/raster/gpu_raster_buffer_provider.cc

 // Copyright 2014 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/raster/gpu_raster_buffer_provider.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 
@@ skipping 31 matching lines @@
     int msaa_sample_count) {
   ScopedGpuRaster gpu_raster(context_provider);
 
   ResourceProvider::ScopedSkSurfaceProvider scoped_surface(
       context_provider, resource_lock, async_worker_context_enabled,
       use_distance_field_text, raster_source->CanUseLCDText(),
       raster_source->HasImpliedColorSpace(), msaa_sample_count);
   SkSurface* sk_surface = scoped_surface.sk_surface();
   // Allocating an SkSurface will fail after a lost context.  Pretend we
   // rasterized, as the contents of the resource don't matter anymore.
-  if (!sk_surface)
+  if (!sk_surface) {
+    DLOG(ERROR) << "Failed to allocate raster surface";
     return;
+  }
 
   // Playback
   gfx::Rect playback_rect = raster_full_rect;
   if (resource_has_previous_content) {
     playback_rect.Intersect(raster_dirty_rect);
   }
   DCHECK(!playback_rect.IsEmpty())
       << "Why are we rastering a tile that's not dirty?";
 
   // Log a histogram of the percentage of pixels that were saved due to
@@ skipping 201 matching lines @@
   gl->OrderingBarrierCHROMIUM();
 
   // Generate sync token after the barrier for cross context synchronization.
   gpu::SyncToken resource_sync_token;
   gl->GenUnverifiedSyncTokenCHROMIUM(fence_sync, resource_sync_token.GetData());
   resource_lock->set_sync_token(resource_sync_token);
   resource_lock->set_synchronized(!async_worker_context_enabled_);
 }
 
 }  // namespace cc