Turning off blending for part of the animation to reduce jank.

This change only turns on blending for the last part
of the minimize and first part of the maximize animation
to save bandwidth and increase frame rate.

This change also properly hides the window only once the animation
is complete instead of cutting off the minimize animation with an
implicit one.

BUG=135177


Review URL: https://chromiumcodereview.appspot.com/10825162

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151271 0039d316-1c4b-4281-b951-d872f2087c98

ash/wm/window_animations.cc

@@ -65,6 +65,7 @@ DEFINE_WINDOW_PROPERTY_KEY(float,
 namespace {
 
 const int kDefaultAnimationDurationForMenuMS = 150;
+const int kLayerAnimationsForMinimizeDurationMS = 350;
 
 // Durations for the cross-fade animation, in milliseconds.
 const float kCrossFadeDurationMinMs = 100.f;
@@ -435,7 +436,8 @@ void AddLayerAnimationsForMinimize(aura::Window* window, bool show) {
 
   rotation_about_pivot->SetReversed(show);
 
-  base::TimeDelta duration = base::TimeDelta::FromMilliseconds(350);
+  base::TimeDelta duration = base::TimeDelta::FromMilliseconds(
+      kLayerAnimationsForMinimizeDurationMS);
 
   scoped_ptr<ui::LayerAnimationElement> transition(
       ui::LayerAnimationElement::CreateInterpolatedTransformElement(
@@ -447,10 +449,23 @@ void AddLayerAnimationsForMinimize(aura::Window* window, bool show) {
   window->layer()->GetAnimator()->ScheduleAnimation(
       new ui::LayerAnimationSequence(transition.release()));
 
+  // When hiding a window, turn off blending until the animation is
+  // 3 / 4 done to save bandwidth and reduce jank
+  if (!show) {
+    ui::LayerAnimationElement::AnimatableProperties propertiesToPause;
+    propertiesToPause.insert(ui::LayerAnimationElement::OPACITY);
+    window->layer()->GetAnimator()->ScheduleAnimation(
+      new ui::LayerAnimationSequence(
+          ui::LayerAnimationElement::CreatePauseElement(
+              propertiesToPause, (duration * 3 ) / 4)));
+  }
+
+  // Fade in and out quickly when the window is small to reduce jank
   float opacity = show ? 1.0f : 0.0f;
   window->layer()->GetAnimator()->ScheduleAnimation(
       new ui::LayerAnimationSequence(
-          ui::LayerAnimationElement::CreateOpacityElement(opacity, duration)));
+          ui::LayerAnimationElement::CreateOpacityElement(
+              opacity, duration / 4)));
 }
 
 void AnimateShowWindow_Minimize(aura::Window* window) {
@@ -469,6 +484,9 @@ void AnimateHideWindow_Minimize(aura::Window* window) {
 
   // Property sets within this scope will be implicitly animated.
   ui::ScopedLayerAnimationSettings settings(window->layer()->GetAnimator());
+  base::TimeDelta duration = base::TimeDelta::FromMilliseconds(
+      kLayerAnimationsForMinimizeDurationMS);
+  settings.SetTransitionDuration(duration);
   settings.AddObserver(new HidingWindowAnimationObserver(window));
   window->layer()->SetVisible(false);