Animations: Port LinkHighlight to use compositor timelines.

Source/web/WebViewImpl.h

Index: Source/web/WebViewImpl.h
diff --git a/Source/web/WebViewImpl.h b/Source/web/WebViewImpl.h
index b5499e88c02e92c0434dd7473471bb7ddcdf541a..09d94fa98921f2a886be4d1c7a516f382b1e7ccf 100644
--- a/Source/web/WebViewImpl.h
+++ b/Source/web/WebViewImpl.h
@@ -37,6 +37,7 @@
 #include "platform/geometry/IntRect.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/heap/Handle.h"
+#include "public/platform/WebCompositorAnimationTimeline.h"
 #include "public/platform/WebDisplayMode.h"
 #include "public/platform/WebFloatSize.h"
 #include "public/platform/WebGestureCurveTarget.h"
@@ -77,7 +78,6 @@ class DeprecatedPaintLayerCompositor;
 class TopControls;
 class UserGestureToken;
 class WebActiveGestureAnimation;
-class WebCompositorAnimationTimeline;
 class WebDevToolsAgentImpl;
 class WebElement;
 class WebLayerTreeView;
@@ -443,6 +443,7 @@ public:
     void scheduleAnimation();
     void attachCompositorAnimationTimeline(WebCompositorAnimationTimeline*);
     void detachCompositorAnimationTimeline(WebCompositorAnimationTimeline*);
+    WebCompositorAnimationTimeline* linkHighlightsTimeline() const { return m_linkHighlightsTimeline.get(); }
 
     virtual void setVisibilityState(WebPageVisibilityState, bool) override;
 
@@ -739,6 +740,7 @@ private:
     int m_flingModifier;
     bool m_flingSourceDevice;
     Vector<OwnPtr<LinkHighlight>> m_linkHighlights;
+    OwnPtr<WebCompositorAnimationTimeline> m_linkHighlightsTimeline;

[chrishtr, 2015/07/13 21:20:53]

Why do you need a timeline specific to link highlights?

[loyso (OOO), 2015/07/14 00:59:04]

Timeline is a group of players, basically. Here we isolate highlight animations
in a special group. (Note that we will rename cc::AnimationPlayer to Animation
and cc::Animation to cc::KeyframeEffect, like here
https://codereview.chromium.org/1113173003/)

In general, highlights use animation system in superficial way. And we want
animation system to be unified with blink to get rid of redundancies.

[chrishtr, 2015/07/14 18:34:00]

Is it actually possible to animate a link highlight?

LinkHighlight is an unfortunate source of one-off complexity that we should
reduce, not increase, which is why we should try to avoid the complexities in
this CL if possible.

[loyso (OOO), 2015/07/15 02:04:36]

Yes, that's an opacity animation if you touch a hyper link on android (What's
funny is that it didn't support --disable-threaded-animation mode).
So, I don't understand the question (given that you started the discussion here:
https://groups.google.com/a/chromium.org/d/msg/paint-dev/b6hEgxo6AbY/gH8snoYW...
)
1) We will delete the old layer-intrusive animation system eventually. All the
conditional branches will be gone.
2) Adding animations directly to layers was a source of highly-coupled code in
chrome compositor. So we needed some external entity to add animations. It's an
AnimationPlayer now.
3) CC animation system is "the least common denominator" for all sub-systems.
And we need to keep LinkHighlights in a working shape.
4) I had the idea to have hidden timeline inside the AnimationHost to handle all
the "orphaned" AnimationPlayers. But this would introduce an unstructured soup
(no grouping == no isolation), which would be hard to debug. So I decided to
keep the group explicit. Moreover, probably we will move some properties (?)
from individual animations into AnimationTimeline.

[chrishtr, 2015/07/15 14:25:14]

It looks like each Document has a timeline already. Can you just re-use the
timeline for the containing document for link highlight animations?

[loyso (OOO), 2015/07/21 01:19:07]

Acknowledged.

     OwnPtrWillBePersistent<FullscreenController> m_fullscreenController;
 
     bool m_showFPSCounter;