cc: Simplify task and its derived classes.

cc/test/fake_tile_manager.cc

Index: cc/test/fake_tile_manager.cc
diff --git a/cc/test/fake_tile_manager.cc b/cc/test/fake_tile_manager.cc
index 77b9b0dfbcf2d46359d3ad824ee22dc280a5e615..1b83c1224e765887d680faa992966d166e99ef84 100644
--- a/cc/test/fake_tile_manager.cc
+++ b/cc/test/fake_tile_manager.cc
@@ -19,13 +19,14 @@ namespace cc {
 
 namespace {
 
-class FakeTileTaskRunnerImpl : public TileTaskRunner, public TileTaskClient {
+class FakeTileTaskRunnerImpl : public TileTaskRunner,
+                               public DependencyTaskClient {
  public:
   // Overridden from TileTaskRunner:
   void Shutdown() override {}
   void ScheduleTasks(TaskGraph* graph) override {
     for (const auto& node : graph->nodes) {
-      RasterTask* task = static_cast<RasterTask*>(node.task);
+      DependencyTask* task = node.task;
 
       task->WillSchedule();
       task->ScheduleOnOriginThread(this);
@@ -35,10 +36,9 @@ class FakeTileTaskRunnerImpl : public TileTaskRunner, public TileTaskClient {
     }
   }
   void CheckForCompletedTasks() override {
-    for (RasterTask::Vector::iterator it = completed_tasks_.begin();
-         it != completed_tasks_.end();
-         ++it) {
-      RasterTask* task = it->get();
+    for (DependencyTask::Vector::iterator it = completed_tasks_.begin();
+         it != completed_tasks_.end(); ++it) {
+      DependencyTask* task = it->get();
 
       task->WillComplete();
       task->CompleteOnOriginThread(this);
@@ -53,7 +53,7 @@ class FakeTileTaskRunnerImpl : public TileTaskRunner, public TileTaskClient {
     return ResourceFormatRequiresSwizzle(GetResourceFormat(must_support_alpha));
   }
 
-  // Overridden from TileTaskClient:
+  // Overridden from DependencyTaskClient:
   scoped_ptr<RasterBuffer> AcquireBufferForRaster(
       const Resource* resource,
       uint64_t resource_content_id,
@@ -63,7 +63,7 @@ class FakeTileTaskRunnerImpl : public TileTaskRunner, public TileTaskClient {
   void ReleaseBufferForRaster(scoped_ptr<RasterBuffer> buffer) override {}
 
  private:
-  RasterTask::Vector completed_tasks_;
+  DependencyTask::Vector completed_tasks_;
 };
 base::LazyInstance<FakeTileTaskRunnerImpl> g_fake_tile_task_runner =
     LAZY_INSTANCE_INITIALIZER;