Show Overlay Scrollbar when GestureScrollUpdate

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 9363993b1b235d12e33e6e6a4e73e4fe502fc9df..193ac57768176005dc5bc21ad78800b5764796ed 100644
--- a/cc/trees/layer_tree_host_impl_unittest.cc
+++ b/cc/trees/layer_tree_host_impl_unittest.cc
@@ -2737,6 +2737,8 @@ class LayerTreeHostImplTestScrollbarAnimation : public LayerTreeHostImplTest {
     settings.scrollbar_animator = animator;
     settings.scrollbar_fade_in_delay = base::TimeDelta::FromMilliseconds(20);
     settings.scrollbar_fade_out_delay = base::TimeDelta::FromMilliseconds(20);
+    settings.scrollbar_fade_out_resize_delay =
+        base::TimeDelta::FromMilliseconds(20);
     settings.scrollbar_fade_out_duration =
         base::TimeDelta::FromMilliseconds(20);
 
@@ -2770,6 +2772,25 @@ class LayerTreeHostImplTestScrollbarAnimation : public LayerTreeHostImplTest {
     EXPECT_EQ(base::TimeDelta(), requested_animation_delay_);
     EXPECT_TRUE(animation_task_.Equals(base::Closure()));
 
+    // If no scroll happened during a scroll gesture, it fades in scrollbars and
+    // schedules a delay fade out.
+    host_impl_->ScrollBegin(BeginState(gfx::Point()).get(),
+                            InputHandler::WHEEL);
+    host_impl_->ScrollBy(UpdateState(gfx::Point(), gfx::Vector2dF(0, 0)).get());
+    host_impl_->ScrollEnd(EndState().get());
+    EXPECT_FALSE(did_request_next_frame_);
+    EXPECT_FALSE(did_request_redraw_);
+    if (expecting_animations) {
+      EXPECT_EQ(base::TimeDelta::FromMilliseconds(20),
+                requested_animation_delay_);
+      EXPECT_FALSE(animation_task_.Equals(base::Closure()));
+      requested_animation_delay_ = base::TimeDelta();
+      animation_task_ = base::Closure();
+    } else {
+      EXPECT_EQ(base::TimeDelta(), requested_animation_delay_);
+      EXPECT_TRUE(animation_task_.Equals(base::Closure()));
+    }
+
     // Before the scrollbar animation exists, we should not get redraws.
     BeginFrameArgs begin_frame_args =
         CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE, 0, 2, fake_now);
@@ -2890,8 +2911,17 @@ class LayerTreeHostImplTestScrollbarAnimation : public LayerTreeHostImplTest {
     host_impl_->ScrollEnd(EndState().get());
     EXPECT_FALSE(did_request_next_frame_);
     EXPECT_FALSE(did_request_redraw_);
-    EXPECT_EQ(base::TimeDelta(), requested_animation_delay_);
-    EXPECT_TRUE(animation_task_.Equals(base::Closure()));
+
+    if (expecting_animations) {
+      EXPECT_EQ(base::TimeDelta::FromMilliseconds(20),
+                requested_animation_delay_);
+      EXPECT_FALSE(animation_task_.Equals(base::Closure()));
+      requested_animation_delay_ = base::TimeDelta();
+      animation_task_ = base::Closure();
+    } else {
+      EXPECT_EQ(base::TimeDelta(), requested_animation_delay_);
+      EXPECT_TRUE(animation_task_.Equals(base::Closure()));
+    }
 
     // Changing page scale triggers scrollbar animation.
     host_impl_->active_tree()->PushPageScaleFromMainThread(1.f, 1.f, 4.f);
@@ -3926,9 +3956,7 @@ class LayerTreeHostImplBrowserControlsTest : public LayerTreeHostImplTest {
   LayerTreeHostImplBrowserControlsTest()
       // Make the clip size the same as the layer (content) size so the layer is
       // non-scrollable.
-      : layer_size_(10, 10),
-        clip_size_(layer_size_),
-        top_controls_height_(50) {
+      : layer_size_(10, 10), clip_size_(layer_size_), top_controls_height_(50) {
     viewport_size_ = gfx::Size(clip_size_.width(),
                                clip_size_.height() + top_controls_height_);
   }