Fix DelegatedOutputSurface in Blimp

blimp/client/support/compositor/blimp_layer_tree_settings.cc

 // Copyright 2015 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 "blimp/client/support/compositor/blimp_layer_tree_settings.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 69 matching lines @@
     // On other devices we have increased memory excessively to avoid
     // raster-on-demand already, so now we reserve 50% _only_ to avoid
     // raster-on-demand, and use 50% of the memory otherwise.
     settings->max_memory_for_prepaint_percentage = 50;
   }
   settings->renderer_settings.should_clear_root_render_pass = true;
 
   // TODO(danakj): Only do this on low end devices.
   settings->create_low_res_tiling = true;
 
-// TODO(dtrainor): Investigate whether or not we want to use an external
-// source here.
-// settings->use_external_begin_frame_source = true;
-
 #elif !defined(OS_MACOSX)
   settings->scrollbar_animator = cc::LayerTreeSettings::LINEAR_FADE;
   settings->solid_color_scrollbar_color = SkColorSetARGB(128, 128, 128, 128);
   settings->scrollbar_fade_delay_ms = 500;
   settings->scrollbar_fade_resize_delay_ms = 500;
   settings->scrollbar_fade_duration_ms = 300;
 
 // When pinching in, only show the pinch-viewport overlay scrollbars if the
 // page scale is at least some threshold away from the minimum. i.e. don't
 // show the pinch scrollbars when at minimum scale.
@@ skipping 112 matching lines @@
 #endif
   settings->default_tile_size.SetSize(default_tile_size, default_tile_size);
 
   settings->renderer_settings.buffer_to_texture_target_map =
       BlimpGpuMemoryBufferManager::GetDefaultBufferToTextureTargetMap();
   settings->use_output_surface_begin_frame_source = true;
 }
 
 }  // namespace client
 }  // namespace blimp