cc: Delay start of scrollbar animation setNeedsRedraw.

cc/scrollbar_animation_controller_linear_fade.cc

 // Copyright 2012 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/scrollbar_animation_controller_linear_fade.h"
 
 #include "base/time.h"
 #include "cc/layer_impl.h"
 
 namespace cc {
@@ skipping 10 matching lines @@
     , m_fadeoutDelay(fadeoutDelay)
     , m_fadeoutLength(fadeoutLength)
     , m_currentTimeForTesting(0)
 {
 }
 
 ScrollbarAnimationControllerLinearFade::~ScrollbarAnimationControllerLinearFade()
 {
 }
 
+double ScrollbarAnimationControllerLinearFade::secondsBeforeStart(base::TimeTicks now) const
+{
+    if (m_lastAwakenTime.is_null())
+        return -1;
+
+    double delta = (now - m_lastAwakenTime).InSecondsF();
+    return std::max(0.0, m_fadeoutDelay - delta);
+}
+
 bool ScrollbarAnimationControllerLinearFade::animate(base::TimeTicks now)
 {
     float opacity = opacityAtTime(now);
     m_scrollLayer->SetScrollbarOpacity(opacity);
-    return opacity;
+    if (!opacity)
+       m_lastAwakenTime = base::TimeTicks();
+    return secondsBeforeStart(now) == 0;
 }
 
 void ScrollbarAnimationControllerLinearFade::didPinchGestureUpdate(base::TimeTicks now)
 {
-    m_pinchGestureInEffect = true;
-}
-
-void ScrollbarAnimationControllerLinearFade::didPinchGestureEnd(base::TimeTicks now)
-{
-    m_pinchGestureInEffect = false;
     m_lastAwakenTime = now;
+    m_scrollLayer->SetScrollbarOpacity(1);
 }
 
 void ScrollbarAnimationControllerLinearFade::didUpdateScrollOffset(base::TimeTicks now)
 {
     m_lastAwakenTime = now;
+    m_scrollLayer->SetScrollbarOpacity(1);
 }
 
 float ScrollbarAnimationControllerLinearFade::opacityAtTime(base::TimeTicks now)
 {
-    if (m_pinchGestureInEffect)
-        return 1;
-
     if (m_lastAwakenTime.is_null())
         return 0;
 
     double delta = (now - m_lastAwakenTime).InSecondsF();
 
     if (delta <= m_fadeoutDelay)
         return 1;
     if (delta < m_fadeoutDelay + m_fadeoutLength)
         return (m_fadeoutDelay + m_fadeoutLength - delta) / m_fadeoutLength;
     return 0;
 }
 
 }  // namespace cc