cc: Remove unused TextureMailboxDeleter from LayerTreeHostImpl.

This was only for DirectRenderers.

R=enne
BUG=606056
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2318953004
Cr-Commit-Position: refs/heads/master@{#417326}

cc/trees/layer_tree_host_impl.cc

@@ -53,7 +53,6 @@
 #include "cc/output/compositor_frame.h"
 #include "cc/output/compositor_frame_metadata.h"
 #include "cc/output/copy_output_request.h"
-#include "cc/output/texture_mailbox_deleter.h"
 #include "cc/quads/render_pass_draw_quad.h"
 #include "cc/quads/shared_quad_state.h"
 #include "cc/quads/solid_color_draw_quad.h"
@@ -230,7 +229,6 @@ LayerTreeHostImpl::LayerTreeHostImpl(
           FrameRateCounter::Create(task_runner_provider_->HasImplThread())),
       memory_history_(MemoryHistory::Create()),
       debug_rect_history_(DebugRectHistory::Create()),
-      texture_mailbox_deleter_(new TextureMailboxDeleter(GetTaskRunner())),
       max_memory_needed_bytes_(0),
       resourceless_software_draw_(false),
       animation_host_(std::move(animation_host)),

cc/trees/layer_tree_host_impl.h

@@ -790,8 +790,6 @@ class CC_EXPORT LayerTreeHostImpl
   std::unique_ptr<MemoryHistory> memory_history_;
   std::unique_ptr<DebugRectHistory> debug_rect_history_;
 
-  std::unique_ptr<TextureMailboxDeleter> texture_mailbox_deleter_;
-
   // The maximum memory that would be used by the prioritized resource
   // manager, if there were no limit on memory usage.
   size_t max_memory_needed_bytes_;