cc: Simplify task and its derived classes.

cc/raster/tile_task_worker_pool_unittest.cc

Index: cc/raster/tile_task_worker_pool_unittest.cc
diff --git a/cc/raster/tile_task_worker_pool_unittest.cc b/cc/raster/tile_task_worker_pool_unittest.cc
index f7613856351ab366ca22483de47a74c169122694..bb9d67c1fda823ec92f645bc2855a7b4bb7579b3 100644
--- a/cc/raster/tile_task_worker_pool_unittest.cc
+++ b/cc/raster/tile_task_worker_pool_unittest.cc
@@ -21,7 +21,6 @@
 #include "cc/raster/gpu_rasterizer.h"
 #include "cc/raster/gpu_tile_task_worker_pool.h"
 #include "cc/raster/one_copy_tile_task_worker_pool.h"
-#include "cc/raster/raster_buffer.h"
 #include "cc/raster/synchronous_task_graph_runner.h"
 #include "cc/raster/tile_task_runner.h"
 #include "cc/raster/zero_copy_tile_task_worker_pool.h"
@@ -51,19 +50,29 @@ enum TileTaskWorkerPoolType {
   TILE_TASK_WORKER_POOL_TYPE_BITMAP
 };
 
-class TestRasterTaskImpl : public RasterTask {
+class TestRasterTaskImpl : public Task {
  public:
   typedef base::Callback<void(bool was_canceled)> Reply;
 
-  TestRasterTaskImpl(const Resource* resource,
-                     const Reply& reply,
-                     ImageDecodeTask::Vector* dependencies)
-      : RasterTask(dependencies),
+  TestRasterTaskImpl(RasterBufferProvider* raster_buffer_provider,
+                     const Resource* resource,
+                     const Reply& reply)
+      : raster_buffer_provider_(raster_buffer_provider),
         resource_(resource),
         reply_(reply),
         raster_source_(FakeRasterSource::CreateFilled(gfx::Size(1, 1))) {}
 
   // Overridden from Task:
+  void ScheduleOnOriginThread() override {
+    // The raster buffer has no tile ids associated with it for partial update,
+    // so doesn't need to provide a valid dirty rect.
+    raster_buffer_ =
+        raster_buffer_provider_->AcquireBufferForRaster(resource_, 0, 0);
+  }
+  void CompleteOnOriginThread() override {
+    raster_buffer_provider_->ReleaseBufferForRaster(std::move(raster_buffer_));
+    reply_.Run(!HasFinishedRunning());
+  }
   void RunOnWorkerThread() override {
     uint64_t new_content_id = 0;
     raster_buffer_->Playback(raster_source_.get(), gfx::Rect(1, 1),
@@ -71,21 +80,11 @@ class TestRasterTaskImpl : public RasterTask {
                              RasterSource::PlaybackSettings());
   }
 
-  // Overridden from TileTask:
-  void ScheduleOnOriginThread(TileTaskClient* client) override {
-    // The raster buffer has no tile ids associated with it for partial update,
-    // so doesn't need to provide a valid dirty rect.
-    raster_buffer_ = client->AcquireBufferForRaster(resource_, 0, 0);
-  }
-  void CompleteOnOriginThread(TileTaskClient* client) override {
-    client->ReleaseBufferForRaster(std::move(raster_buffer_));
-    reply_.Run(!HasFinishedRunning());
-  }
-
  protected:
   ~TestRasterTaskImpl() override {}
 
  private:
+  RasterBufferProvider* raster_buffer_provider_;
   const Resource* resource_;
   const Reply reply_;
   scoped_ptr<RasterBuffer> raster_buffer_;
@@ -96,11 +95,12 @@ class TestRasterTaskImpl : public RasterTask {
 
 class BlockingTestRasterTaskImpl : public TestRasterTaskImpl {
  public:
-  BlockingTestRasterTaskImpl(const Resource* resource,
+  BlockingTestRasterTaskImpl(RasterBufferProvider* raster_buffer_provider,
+                             const Resource* resource,
                              const Reply& reply,
-                             base::Lock* lock,
-                             ImageDecodeTask::Vector* dependencies)
-      : TestRasterTaskImpl(resource, reply, dependencies), lock_(lock) {}
+                             base::Lock* lock)
+      : TestRasterTaskImpl(raster_buffer_provider, resource, reply),
+        lock_(lock) {}
 
   // Overridden from Task:
   void RunOnWorkerThread() override {
@@ -125,7 +125,7 @@ class TileTaskWorkerPoolTest
     bool canceled;
   };
 
-  typedef std::vector<scoped_refptr<RasterTask>> RasterTaskVector;
+  typedef std::vector<scoped_refptr<Task>> RasterTaskVector;
 
   enum NamedTaskSet { REQUIRED_FOR_ACTIVATION, REQUIRED_FOR_DRAW, ALL };
 
@@ -210,12 +210,10 @@ class TileTaskWorkerPoolTest
                        RGBA_8888);
     const Resource* const_resource = resource.get();
 
-    ImageDecodeTask::Vector empty;
     tasks_.push_back(new TestRasterTaskImpl(
-        const_resource,
+        tile_task_worker_pool_->AsTileTaskRunner(), const_resource,
         base::Bind(&TileTaskWorkerPoolTest::OnTaskCompleted,
-                   base::Unretained(this), base::Passed(&resource), id),
-        &empty));
+                   base::Unretained(this), base::Passed(&resource), id)));
   }
 
   void AppendTask(unsigned id) { AppendTask(id, gfx::Size(1, 1)); }
@@ -229,12 +227,11 @@ class TileTaskWorkerPoolTest
                        RGBA_8888);
     const Resource* const_resource = resource.get();
 
-    ImageDecodeTask::Vector empty;
     tasks_.push_back(new BlockingTestRasterTaskImpl(
-        const_resource,
+        tile_task_worker_pool_->AsTileTaskRunner(), const_resource,
         base::Bind(&TileTaskWorkerPoolTest::OnTaskCompleted,
                    base::Unretained(this), base::Passed(&resource), id),
-        lock, &empty));
+        lock));
   }
 
   const std::vector<RasterTaskResult>& completed_tasks() const {