[Android]Optimization of scrollbar animation.

cc/trees/layer_tree_host_impl_unittest.cc

Index: cc/trees/layer_tree_host_impl_unittest.cc
diff --git a/cc/trees/layer_tree_host_impl_unittest.cc b/cc/trees/layer_tree_host_impl_unittest.cc
index 94ecb174c14ba231f2878b3986533fa04bbc50a7..9e63fad82d87448da4d85c965d6da37f423cab13 100644
--- a/cc/trees/layer_tree_host_impl_unittest.cc
+++ b/cc/trees/layer_tree_host_impl_unittest.cc
@@ -1359,7 +1359,7 @@ TEST_F(LayerTreeHostImplTest, ScrollbarLinearFadeScheduling) {
 
   // After a scroll, a fade animation should be scheduled about 20ms from now.
   host_impl_->ScrollBegin(gfx::Point(), InputHandler::Wheel);
-  host_impl_->ScrollBy(gfx::Point(), gfx::Vector2dF(5, 0));
+  host_impl_->ScrollBy(gfx::Point(), gfx::Vector2dF(0, 5));

[weiliangc, 2014/09/16 16:02:11]

Just want to make sure, why would this fix the test crash? What is the reason
for crash in the first place?

[MuVen, 2014/09/16 16:10:14]

Crash in the sense Expect_LT has failed.Sorry or my confusing english. In this
test Vertical Scrollbar is created and there is scrollby by offset in horizontal
direction, due to which there is no change for vertical scrollbar layer
properties(because of my patch), due to which animation is not triggered and
because of which EXPECT_LT has failed after scrollend.
On 2014/09/16 16:02:11, weiliangc wrote:

   host_impl_->ScrollEnd();
   did_request_redraw_ = false;
   did_request_animate_ = false;
@@ -1386,6 +1386,12 @@ TEST_F(LayerTreeHostImplTest, ScrollbarLinearFadeScheduling) {
   EXPECT_FALSE(did_request_redraw_);
   EXPECT_FALSE(did_request_animate_);
   requested_scrollbar_animation_delay_ = base::TimeDelta();
+
+  // Unnecessarily Fade animation of solid color scrollbar is not triggered.
+  host_impl_->ScrollBegin(gfx::Point(), InputHandler::Wheel);
+  host_impl_->ScrollBy(gfx::Point(), gfx::Vector2dF(5, 0));
+  host_impl_->ScrollEnd();
+  EXPECT_EQ(base::TimeDelta(), requested_scrollbar_animation_delay_);
 }
 
 TEST_F(LayerTreeHostImplTest, ScrollbarFadePinchZoomScrollbars) {