Cleanup: Removing unused code in DelegatedRendererLayer

It was added as a part of this patch
https://chromiumcodereview.appspot.com/24078024

Review URL: https://codereview.chromium.org/598643002

Cr-Commit-Position: refs/heads/master@{#296225}

cc/layers/delegated_renderer_layer.cc

@@ -7,7 +7,6 @@
 #include "cc/layers/delegated_renderer_layer_impl.h"
 #include "cc/output/delegated_frame_data.h"
 #include "cc/quads/render_pass_draw_quad.h"
-#include "cc/trees/blocking_task_runner.h"
 #include "cc/trees/layer_tree_host.h"
 
 namespace cc {

cc/layers/delegated_renderer_layer.h

@@ -15,7 +15,6 @@
 #include "cc/resources/returned_resource.h"
 
 namespace cc {
-class BlockingTaskRunner;
 
 class CC_EXPORT DelegatedRendererLayer : public Layer {
  public: