Observe LCD text restrictions during layer animations

Drawing LCD text into non-opaque layers is never correct - we should
update DrawProperties.can_use_lcd_text during animations also.

BUG=486892
R=danakj@chromium.org,enne@chromium.org

Review URL: https://codereview.chromium.org/1132253003

Cr-Commit-Position: refs/heads/master@{#329705}

2 files changed, 27 insertions, 8 deletions

diff --git a/cc/trees/layer_tree_host_common.cc b/cc/trees/layer_tree_host_common.cc
index 49bc13d..0988285 100644
--- a/cc/trees/layer_tree_host_common.cc
+++ b/cc/trees/layer_tree_host_common.cc
@@ -1897,10 +1897,6 @@ static void CalculateDrawPropertiesInternal(
   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;
   bool layer_can_use_lcd_text = true;
   bool subtree_can_use_lcd_text = true;
   if (!globals.layers_always_allowed_lcd_text) {
@@ -2145,8 +2141,7 @@ static void CalculateDrawPropertiesInternal(
     layer_draw_properties.render_target = layer->parent()->render_target();
   }
 
-  if (adjust_text_aa)
-    layer_draw_properties.can_use_lcd_text = layer_can_use_lcd_text;
+  layer_draw_properties.can_use_lcd_text = layer_can_use_lcd_text;
 
   gfx::Size content_size_affected_by_delta(layer->content_bounds());
 
diff --git a/cc/trees/layer_tree_host_common_unittest.cc b/cc/trees/layer_tree_host_common_unittest.cc
index bcd437f..591f48c 100644
--- a/cc/trees/layer_tree_host_common_unittest.cc
+++ b/cc/trees/layer_tree_host_common_unittest.cc
@@ -5977,6 +5977,7 @@ TEST_P(LCDTextTest, CanUseLCDText) {
 
 TEST_P(LCDTextTest, CanUseLCDTextWithAnimation) {
   bool expect_lcd_text = can_use_lcd_text_ || layers_always_allowed_lcd_text_;
+  bool expect_not_lcd_text = layers_always_allowed_lcd_text_;
 
   // Sanity check: Make sure can_use_lcd_text_ is set on each node.
   ExecuteCalculateDrawProperties(root_, 1.f, 1.f, NULL, can_use_lcd_text_,
@@ -5992,11 +5993,34 @@ TEST_P(LCDTextTest, CanUseLCDTextWithAnimation) {
 
   ExecuteCalculateDrawProperties(root_, 1.f, 1.f, NULL, can_use_lcd_text_,
                                  layers_always_allowed_lcd_text_);
-  // Text AA should not be adjusted while animation is active.
-  // Make sure LCD text AA setting remains unchanged.
+  // Text LCD should be adjusted while animation is active.
+  EXPECT_EQ(expect_lcd_text, root_->can_use_lcd_text());
+  EXPECT_EQ(expect_not_lcd_text, child_->can_use_lcd_text());
+  EXPECT_EQ(expect_not_lcd_text, grand_child_->can_use_lcd_text());
+}
+
+TEST_P(LCDTextTest, CanUseLCDTextWithAnimationContentsOpaque) {
+  bool expect_lcd_text = can_use_lcd_text_ || layers_always_allowed_lcd_text_;
+  bool expect_not_lcd_text = layers_always_allowed_lcd_text_;
+
+  // Sanity check: Make sure can_use_lcd_text_ is set on each node.
+  ExecuteCalculateDrawProperties(root_, 1.f, 1.f, NULL, can_use_lcd_text_,
+                                 layers_always_allowed_lcd_text_);
   EXPECT_EQ(expect_lcd_text, root_->can_use_lcd_text());
   EXPECT_EQ(expect_lcd_text, child_->can_use_lcd_text());
   EXPECT_EQ(expect_lcd_text, grand_child_->can_use_lcd_text());
+
+  // Mark contents non-opaque within the first animation frame.
+  child_->SetContentsOpaque(false);
+  AddOpacityTransitionToController(child_->layer_animation_controller(), 10.0,
+                                   0.9f, 0.1f, false);
+
+  ExecuteCalculateDrawProperties(root_, 1.f, 1.f, NULL, can_use_lcd_text_,
+                                 layers_always_allowed_lcd_text_);
+  // LCD text should be disabled for non-opaque layers even during animations.
+  EXPECT_EQ(expect_lcd_text, root_->can_use_lcd_text());
+  EXPECT_EQ(expect_not_lcd_text, child_->can_use_lcd_text());
+  EXPECT_EQ(expect_lcd_text, grand_child_->can_use_lcd_text());
 }
 
 INSTANTIATE_TEST_CASE_P(LayerTreeHostCommonTest,