cc: Toggle LCD text at raster time instead of record time.

cc/trees/layer_tree_host_common.cc

 // 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.
 
 #include "cc/trees/layer_tree_host_common.h"
 
 #include <algorithm>
 
 #include "base/debug/trace_event.h"
 #include "cc/base/math_util.h"
@@ skipping 1251 matching lines @@
 
 template <typename LayerType>
 struct SubtreeGlobals {
   LayerSorter* layer_sorter;
   int max_texture_size;
   float device_scale_factor;
   float page_scale_factor;
   const LayerType* page_scale_application_layer;
   bool can_adjust_raster_scales;
   bool can_render_to_separate_surface;
+  bool layers_always_allowed_lcd_text;
 };
 
 template<typename LayerType>
 struct DataForRecursion {
   // The accumulated sequence of transforms a layer will use to determine its
   // own draw transform.
   gfx::Transform parent_matrix;
 
   // The accumulated sequence of transforms a layer will use to determine its
   // own screen-space transform.
@@ skipping 502 matching lines @@
       data_from_ancestor.full_hierarchy_matrix;
   if (layer->should_flatten_transform())
     layer_draw_properties.screen_space_transform.FlattenTo2d();
   layer_draw_properties.screen_space_transform.PreconcatTransform
       (layer_draw_properties.target_space_transform);
 
   // Adjusting text AA method during animation may cause repaints, which in-turn
   // causes jank.
   bool adjust_text_aa =
       !animating_opacity_to_screen && !animating_transform_to_screen;
-  // To avoid color fringing, LCD text should only be used on opaque layers with
-  // just integral translation.
-  bool layer_can_use_lcd_text =
-      data_from_ancestor.subtree_can_use_lcd_text &&
-      accumulated_draw_opacity == 1.f &&
-      layer_draw_properties.target_space_transform.
-          IsIdentityOrIntegerTranslation();
+  bool layer_can_use_lcd_text = true;
+  if (!globals.layers_always_allowed_lcd_text) {
+    // To avoid color fringing, LCD text should only be used on opaque layers
+    // with just integral translation.
+    layer_can_use_lcd_text = data_from_ancestor.subtree_can_use_lcd_text &&
+                             accumulated_draw_opacity == 1.f &&
+                             layer_draw_properties.target_space_transform
+                                 .IsIdentityOrIntegerTranslation();
+  }
 
   gfx::Rect content_rect(layer->content_bounds());
 
   // full_hierarchy_matrix is the matrix that transforms objects between screen
   // space (except projection matrix) and the most recent RenderSurfaceImpl's
   // space.  next_hierarchy_matrix will only change if this layer uses a new
   // RenderSurfaceImpl, otherwise remains the same.
   data_for_children.full_hierarchy_matrix =
       data_from_ancestor.full_hierarchy_matrix;
 
@@ skipping 556 matching lines @@
 
   globals->layer_sorter = NULL;
   globals->max_texture_size = inputs.max_texture_size;
   globals->device_scale_factor =
       inputs.device_scale_factor * device_transform_scale;
   globals->page_scale_factor = inputs.page_scale_factor;
   globals->page_scale_application_layer = inputs.page_scale_application_layer;
   globals->can_render_to_separate_surface =
       inputs.can_render_to_separate_surface;
   globals->can_adjust_raster_scales = inputs.can_adjust_raster_scales;
+  globals->layers_always_allowed_lcd_text =
+      inputs.layers_always_allowed_lcd_text;
 
   data_for_recursion->parent_matrix = scaled_device_transform;
   data_for_recursion->full_hierarchy_matrix = identity_matrix;
   data_for_recursion->scroll_compensation_matrix = identity_matrix;
   data_for_recursion->fixed_container = inputs.root_layer;
   data_for_recursion->clip_rect_in_target_space = device_viewport_rect;
   data_for_recursion->clip_rect_of_target_surface_in_target_space =
       device_viewport_rect;
   data_for_recursion->maximum_animation_contents_scale = 0.f;
   data_for_recursion->ancestor_is_animating_scale = false;
@@ skipping 53 matching lines @@
       inputs->current_render_surface_layer_list_id);
 
   // The dummy layer list should not have been used.
   DCHECK_EQ(0u, dummy_layer_list.size());
   // A root layer render_surface should always exist after
   // CalculateDrawProperties.
   DCHECK(inputs->root_layer->render_surface());
 }
 
 }  // namespace cc