Define a --force-gpu-rasterization flag

cc/trees/layer_tree_settings.h

 // Copyright 2011 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.
 
 #ifndef CC_TREES_LAYER_TREE_SETTINGS_H_
 #define CC_TREES_LAYER_TREE_SETTINGS_H_
 
 #include "base/basictypes.h"
 #include "cc/base/cc_export.h"
 #include "cc/debug/layer_tree_debug_state.h"
@@ skipping 11 matching lines @@
   bool allow_antialiasing;
   bool throttle_frame_production;
   bool begin_impl_frame_scheduling_enabled;
   bool using_synchronous_renderer_compositor;
   bool per_tile_painting_enabled;
   bool partial_swap_enabled;
   bool accelerated_animation_enabled;
   bool show_overdraw_in_tracing;
   bool can_use_lcd_text;
   bool should_clear_root_render_pass;
-  bool gpu_rasterization;
+  enum RasterizationSite {
+    CpuRasterization,
+    HybridRasterization,
+    GpuRasterization,
+  };
+  RasterizationSite rasterization_site;
 
   enum ScrollbarAnimator {
     NoAnimator,
     LinearFade,
     Thinning,
   };
   ScrollbarAnimator scrollbar_animator;
   int scrollbar_linear_fade_delay_ms;
   int scrollbar_linear_fade_length_ms;
   SkColor solid_color_scrollbar_color;
@@ skipping 26 matching lines @@
   bool use_rgba_4444_textures;
   bool touch_hit_testing;
   size_t texture_id_allocation_chunk_size;
 
   LayerTreeDebugState initial_debug_state;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_SETTINGS_H_