gfx: Add FrameTime and DisplayTime classes

cc/animation/scrollbar_animation_controller_linear_fade.cc

Index: cc/animation/scrollbar_animation_controller_linear_fade.cc
diff --git a/cc/animation/scrollbar_animation_controller_linear_fade.cc b/cc/animation/scrollbar_animation_controller_linear_fade.cc
index 863959b84c27691f9afe1cca9628b399fc3b04e9..52298d19aeda08a1f2ffd5e6ad9d579b66dae4e7 100644
--- a/cc/animation/scrollbar_animation_controller_linear_fade.cc
+++ b/cc/animation/scrollbar_animation_controller_linear_fade.cc
@@ -37,17 +37,17 @@ bool ScrollbarAnimationControllerLinearFade::IsAnimating() const {
 }
 
 base::TimeDelta ScrollbarAnimationControllerLinearFade::DelayBeforeStart(
-    base::TimeTicks now) const {
+    gfx::FrameTime now) const {
   if (now > last_awaken_time_ + fadeout_delay_)
     return base::TimeDelta();
   return fadeout_delay_ - (now - last_awaken_time_);
 }
 
-bool ScrollbarAnimationControllerLinearFade::Animate(base::TimeTicks now) {
+bool ScrollbarAnimationControllerLinearFade::Animate(gfx::FrameTime now) {
   float opacity = OpacityAtTime(now);
   ApplyOpacityToScrollbars(opacity);
   if (!opacity)
-    last_awaken_time_ = base::TimeTicks();
+    last_awaken_time_ = gfx::FrameTime();
   return IsAnimating() && DelayBeforeStart(now) == base::TimeDelta();
 }
 
@@ -57,7 +57,7 @@ void ScrollbarAnimationControllerLinearFade::DidScrollGestureBegin() {
 }
 
 void ScrollbarAnimationControllerLinearFade::DidScrollGestureEnd(
-    base::TimeTicks now) {
+    gfx::FrameTime now) {
   // The animation should not be triggered if no scrolling has occurred.
   if (scroll_gesture_has_scrolled_)
     last_awaken_time_ = now;
@@ -65,18 +65,18 @@ void ScrollbarAnimationControllerLinearFade::DidScrollGestureEnd(
   scroll_gesture_in_progress_ = false;
 }
 
-void ScrollbarAnimationControllerLinearFade::DidMouseMoveOffScrollbar(
-    base::TimeTicks now) {
+void ScrollbarAnimationControllerLinearFade::DidMouseMoveOffScrollbar(\
+    gfx::FrameTime now) {
   // Ignore mouse move events.
 }
 
 bool ScrollbarAnimationControllerLinearFade::DidScrollUpdate(
-    base::TimeTicks now) {
+    gfx::FrameTime now) {
   ApplyOpacityToScrollbars(1.0f);
   // The animation should only be activated if the scroll updated occurred
   // programatically, outside the scope of a scroll gesture.
   if (scroll_gesture_in_progress_) {
-    last_awaken_time_ = base::TimeTicks();
+    last_awaken_time_ = gfx::FrameTime();
     scroll_gesture_has_scrolled_ = true;
     return false;
   }
@@ -86,13 +86,13 @@ bool ScrollbarAnimationControllerLinearFade::DidScrollUpdate(
 }
 
 bool ScrollbarAnimationControllerLinearFade::DidMouseMoveNear(
-    base::TimeTicks now, float distance) {
+    gfx::FrameTime now, float distance) {
   // Ignore mouse move events.
   return false;
 }
 
 float ScrollbarAnimationControllerLinearFade::OpacityAtTime(
-    base::TimeTicks now) {
+    gfx::FrameTime now) {
   if (scroll_gesture_has_scrolled_)
     return 1.0f;