Add better support for RGBA_4444 textures.

ui/compositor/compositor.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/compositor/compositor.h"
 
 #include <algorithm>
 #include <deque>
 
 #include "base/bind.h"
@@ skipping 121 matching lines @@
       command_line->HasSwitch(cc::switches::kUIShowReplicaScreenSpaceRects);
 
   settings.initial_debug_state.SetRecordRenderingStats(
       command_line->HasSwitch(cc::switches::kEnableGpuBenchmarking));
 
   settings.use_display_lists = true;
 
   settings.use_zero_copy = IsUIZeroCopyEnabled();
   settings.use_one_copy = IsUIOneCopyEnabled();
 
+  settings.renderer_settings.use_rgba_4444_textures =
+      command_line->HasSwitch(switches::kUIEnableRGBA4444Textures);
+
   // Use PERSISTENT_MAP memory buffers to support partial tile raster for
   // software raster into GpuMemoryBuffers.
   gfx::BufferUsage usage = gfx::BufferUsage::PERSISTENT_MAP;
   settings.use_persistent_map_for_gpu_memory_buffers = true;
 
   for (size_t format = 0;
       format < static_cast<size_t>(gfx::BufferFormat::LAST) + 1; format++) {
     DCHECK_GT(settings.use_image_texture_targets.size(), format);
     settings.use_image_texture_targets[format] =
         context_factory_->GetImageTextureTarget(
@@ skipping 305 matching lines @@
                     observer_list_,
                     OnCompositingLockStateChanged(this));
 }
 
 void Compositor::CancelCompositorLock() {
   if (compositor_lock_)
     compositor_lock_->CancelLock();
 }
 
 }  // namespace ui