Gradient overlay for constrained window

ui/base/animation/linear_animation.cc

 // Copyright (c) 2011 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 "ui/base/animation/linear_animation.h"
 
 #include <math.h>
 
 #include "ui/base/animation/animation_container.h"
 #include "ui/base/animation/animation_delegate.h"
@@ skipping 27 matching lines @@
       in_end_(false) {
   set_delegate(delegate);
   SetDuration(duration);
 }
 
 double LinearAnimation::GetCurrentValue() const {
   // Default is linear relationship, subclass to adapt.
   return state_;
 }
 
+void LinearAnimation::SetCurrentValue(double new_value) {
+  new_value = std::max(0.0, std::min(1.0, new_value));
+  base::TimeDelta time_delta = base::TimeDelta::FromMicroseconds(
+      duration_.InMicroseconds() * (new_value - state_));
+  SetStartTime(start_time() - time_delta);
+  state_ = new_value;
+}
+
 void LinearAnimation::End() {
   if (!is_animating())
     return;
 
   // NOTE: We don't use AutoReset here as Stop may end up deleting us (by way
   // of the delegate).
   in_end_ = true;
   Stop();
 }
 
@@ skipping 14 matching lines @@
 
   AnimateToState(state_);
 
   if (delegate())
     delegate()->AnimationProgressed(this);
 
   if (state_ == 1.0)
     Stop();
 }
 
+void LinearAnimation::AnimationStarted() {
+  state_ = 0.0;
+}
+
 void LinearAnimation::AnimationStopped() {
   if (!in_end_)
     return;
 
   in_end_ = false;
   // Set state_ to ensure we send ended to delegate and not canceled.
   state_ = 1;
   AnimateToState(1.0);
 }
 
 bool LinearAnimation::ShouldSendCanceledFromStop() {
   return state_ != 1;
 }
 
 }  // namespace ui