Hide location bar on WebKit programmatic scroll.

cc/input/top_controls_manager.cc

Index: cc/input/top_controls_manager.cc
diff --git a/cc/input/top_controls_manager.cc b/cc/input/top_controls_manager.cc
index e1698f1316cbd626d7a500ca81ae2cd273b10131..f09644abc336b7dedab1c35dd9b6f704520c4ee1 100644
--- a/cc/input/top_controls_manager.cc
+++ b/cc/input/top_controls_manager.cc
@@ -60,10 +60,16 @@ void TopControlsManager::EnableHidingTopControls(bool enable) {
 
   if (!enable) {
     ResetAnimations();
-    if (controls_top_offset_ != 0) {
-      SetupAnimation(SHOWING_CONTROLS);
-      client_->setNeedsRedraw();
-    }
+    SetupAnimation(SHOWING_CONTROLS);
+  }
+}
+
+void TopControlsManager::ShowTopControls(bool show) {
+  if (show) {
+    SetupAnimation(SHOWING_CONTROLS);
+  } else {
+    DCHECK(enable_hiding_);
+    SetupAnimation(HIDING_CONTROLS);
   }
 }
 
@@ -137,6 +143,18 @@ void TopControlsManager::ResetAnimations() {
 }
 
 void TopControlsManager::SetupAnimation(AnimationDirection direction) {
+  DCHECK(direction != NO_ANIMATION);
+
+  if (direction == SHOWING_CONTROLS && controls_top_offset_ == 0)
+    return;
+
+  if (direction == HIDING_CONTROLS &&
+      controls_top_offset_ == -top_controls_height_)
+    return;
+
+  if (top_controls_animation_ && animation_direction_ == direction)
+    return;
+
   top_controls_animation_ = KeyframedFloatAnimationCurve::Create();
   double start_time =
       (base::TimeTicks::Now() - base::TimeTicks()).InMillisecondsF();
@@ -150,6 +168,7 @@ void TopControlsManager::SetupAnimation(AnimationDirection direction) {
                             controls_top_offset_ + max_ending_offset,
                             EaseTimingFunction::Create()));
   animation_direction_ = direction;
+  client_->setNeedsRedraw();
 }
 
 void TopControlsManager::StartAnimationIfNecessary() {
@@ -171,11 +190,8 @@ void TopControlsManager::StartAnimationIfNecessary() {
           SHOWING_CONTROLS : HIDING_CONTROLS;
     }
 
-    if (show_controls != NO_ANIMATION &&
-        (!top_controls_animation_ || animation_direction_ != show_controls)) {
+    if (show_controls != NO_ANIMATION)
       SetupAnimation(show_controls);
-      client_->setNeedsRedraw();
-    }
   }
 }