Add preliminary support for hw-accelerated tile rasterization.

cc/resources/pixel_buffer_raster_worker_pool.h

Index: cc/resources/pixel_buffer_raster_worker_pool.h
diff --git a/cc/resources/pixel_buffer_raster_worker_pool.h b/cc/resources/pixel_buffer_raster_worker_pool.h
index 88be2c02a7f8901cc5899eefefe8bd65256bf463..d5538b169f7a2b49a11d185c5a1ac3e6c1a751f0 100644
--- a/cc/resources/pixel_buffer_raster_worker_pool.h
+++ b/cc/resources/pixel_buffer_raster_worker_pool.h
@@ -20,10 +20,12 @@ class CC_EXPORT PixelBufferRasterWorkerPool : public RasterWorkerPool {
 
   static scoped_ptr<RasterWorkerPool> Create(
       ResourceProvider* resource_provider,
+      ContextProvider* context_provider,
       size_t num_threads,
       size_t max_transfer_buffer_usage_bytes) {
     return make_scoped_ptr<RasterWorkerPool>(
         new PixelBufferRasterWorkerPool(resource_provider,
+                                        context_provider,
                                         num_threads,
                                         max_transfer_buffer_usage_bytes));
   }
@@ -41,6 +43,7 @@ class CC_EXPORT PixelBufferRasterWorkerPool : public RasterWorkerPool {
 
  private:
   PixelBufferRasterWorkerPool(ResourceProvider* resource_provider,
+                              ContextProvider* context_provider,
                               size_t num_threads,
                               size_t max_transfer_buffer_usage_bytes);