cc: Simplify task and its derived classes.

cc/raster/gpu_tile_task_worker_pool.h

Index: cc/raster/gpu_tile_task_worker_pool.h
diff --git a/cc/raster/gpu_tile_task_worker_pool.h b/cc/raster/gpu_tile_task_worker_pool.h
index 0577b51fdfb70e1ac620bbe491a049f2a4d4ba59..693b053c2010562865d2584f095b05745ca16735 100644
--- a/cc/raster/gpu_tile_task_worker_pool.h
+++ b/cc/raster/gpu_tile_task_worker_pool.h
@@ -18,7 +18,7 @@ class ResourceProvider;
 
 class CC_EXPORT GpuTileTaskWorkerPool : public TileTaskWorkerPool,
                                         public TileTaskRunner,
-                                        public TileTaskClient {
+                                        public DependencyTaskClient {
  public:
   ~GpuTileTaskWorkerPool() override;
 
@@ -40,7 +40,7 @@ class CC_EXPORT GpuTileTaskWorkerPool : public TileTaskWorkerPool,
   ResourceFormat GetResourceFormat(bool must_support_alpha) const override;
   bool GetResourceRequiresSwizzle(bool must_support_alpha) const override;
 
-  // Overridden from TileTaskClient:
+  // Overridden from DependencyTaskClient:
   scoped_ptr<RasterBuffer> AcquireBufferForRaster(
       const Resource* resource,
       uint64_t resource_content_id,
@@ -55,14 +55,14 @@ class CC_EXPORT GpuTileTaskWorkerPool : public TileTaskWorkerPool,
                         bool use_distance_field_text,
                         int gpu_rasterization_msaa_sample_count);
 
-  void CompleteTasks(const Task::Vector& tasks);
+  void CompleteTasks(const DependencyTask::Vector& tasks);
 
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
   TaskGraphRunner* task_graph_runner_;
   const NamespaceToken namespace_token_;
   scoped_ptr<GpuRasterizer> rasterizer_;
 
-  Task::Vector completed_tasks_;
+  DependencyTask::Vector completed_tasks_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuTileTaskWorkerPool);
 };