Devtools Animations: Add buffer and effect selection to animation timeline

Source/devtools/front_end/animation/AnimationModel.js

Index: Source/devtools/front_end/animation/AnimationModel.js
diff --git a/Source/devtools/front_end/animation/AnimationModel.js b/Source/devtools/front_end/animation/AnimationModel.js
index 09e30fd25b2c5d91cbdc8010c7291169f674bedb..b692148699caf0b34fa738014f2e3bcd7a7c8669 100644
--- a/Source/devtools/front_end/animation/AnimationModel.js
+++ b/Source/devtools/front_end/animation/AnimationModel.js
@@ -22,7 +22,7 @@ WebInspector.AnimationModel = function(target)
 }
 
 WebInspector.AnimationModel.Events = {
-    AnimationCreated: "AnimationCreated",
+    AnimationGroupStarted: "AnimationGroupStarted",
     AnimationCanceled: "AnimationCanceled"
 }
 
@@ -51,9 +51,7 @@ WebInspector.AnimationModel.prototype = {
         while (this._pendingAnimations.length) {
             var group = this._createGroupFromPendingAnimations();
             this._animationGroups.set(group.id(), group);
-            // TODO(samli): Dispatch single group event.
-            for (var anim of group.animations())
-                this.dispatchEventToListeners(WebInspector.AnimationModel.Events.AnimationCreated, { "player": anim, "resetTimeline": anim.id() === group.id() });
+            this.dispatchEventToListeners(WebInspector.AnimationModel.Events.AnimationGroupStarted, group);
         }
     },
 
@@ -519,6 +517,14 @@ WebInspector.AnimationModel.AnimationGroup.prototype = {
         return this._animations;
     },
 
+    /**
+     * @return {number}
+     */
+    startTime: function()
+    {
+        return this._animations[0].startTime();
+    },
+
     __proto__: WebInspector.SDKObject.prototype
 }