cc: Simplify task and its derived classes.

cc/tiles/gpu_image_decode_controller.cc

Index: cc/tiles/gpu_image_decode_controller.cc
diff --git a/cc/tiles/gpu_image_decode_controller.cc b/cc/tiles/gpu_image_decode_controller.cc
index da9bd207010071c937c8c6490c1d6511db1b7ab8..afb0e9554b301c2cf920a7e301a9496ea11714af 100644
--- a/cc/tiles/gpu_image_decode_controller.cc
+++ b/cc/tiles/gpu_image_decode_controller.cc
@@ -10,7 +10,7 @@
 
 namespace cc {
 
-class ImageDecodeTaskImpl : public ImageDecodeTask {
+class ImageDecodeTaskImpl : public DependencyTask {
  public:
   ImageDecodeTaskImpl(GpuImageDecodeController* controller,
                       const DrawImage& image,
@@ -20,7 +20,7 @@ class ImageDecodeTaskImpl : public ImageDecodeTask {
         image_ref_(skia::SharePtr(image.image())),
         source_prepare_tiles_id_(source_prepare_tiles_id) {}
 
-  // Overridden from Task:
+  // Overridden from DependencyTask:
   void RunOnWorkerThread() override {
     TRACE_EVENT2("cc", "ImageDecodeTaskImpl::RunOnWorkerThread", "mode", "gpu",
                  "source_prepare_tiles_id", source_prepare_tiles_id_);
@@ -28,10 +28,8 @@ class ImageDecodeTaskImpl : public ImageDecodeTask {
         image_ref_.get());
     controller_->DecodeImage(image_);
   }
-
-  // Overridden from TileTask:
-  void ScheduleOnOriginThread(TileTaskClient* client) override {}
-  void CompleteOnOriginThread(TileTaskClient* client) override {
+  void ScheduleOnOriginThread(DependencyTaskClient* client) override {}
+  void CompleteOnOriginThread(DependencyTaskClient* client) override {
     controller_->RemovePendingTaskForImage(image_);
   }
 
@@ -54,7 +52,7 @@ GpuImageDecodeController::~GpuImageDecodeController() {}
 bool GpuImageDecodeController::GetTaskForImageAndRef(
     const DrawImage& image,
     uint64_t prepare_tiles_id,
-    scoped_refptr<ImageDecodeTask>* task) {
+    scoped_refptr<DependencyTask>* task) {
   auto image_id = image.image()->uniqueID();
   base::AutoLock lock(lock_);
   if (prerolled_images_.count(image_id) != 0) {
@@ -62,8 +60,7 @@ bool GpuImageDecodeController::GetTaskForImageAndRef(
     return false;
   }
 
-  scoped_refptr<ImageDecodeTask>& existing_task =
-      pending_image_tasks_[image_id];
+  scoped_refptr<DependencyTask>& existing_task = pending_image_tasks_[image_id];
   if (!existing_task) {
     existing_task = make_scoped_refptr(
         new ImageDecodeTaskImpl(this, image, prepare_tiles_id));