Changing animate to beginFrame and use struct rather than naked double to allow extension.

public/web/WebWidget.h

Index: public/web/WebWidget.h
diff --git a/public/web/WebWidget.h b/public/web/WebWidget.h
index 54b00f3506d41f3f114ebfb022abf5ac6b577916..0a110593eb584ed995771cb226e044368fdcc70b 100644
--- a/public/web/WebWidget.h
+++ b/public/web/WebWidget.h
@@ -33,6 +33,7 @@
 
 #include "../platform/WebCanvas.h"
 #include "../platform/WebCommon.h"
+#include "../platform/WebFrameTime.h"
 #include "../platform/WebRect.h"
 #include "../platform/WebSize.h"
 #include "WebCompositionUnderline.h"
@@ -88,7 +89,17 @@ public:
 
     // Called to update imperative animation state. This should be called before
     // paint, although the client can rate-limit these calls.
-    virtual void animate(double monotonicFrameBeginTime) { }
+    // FIXME(mithro): Remove this function once Chrome side patch lands.
+    void animate(double monotonicFrameBeginTime)
+    {
+        animate(
+            WebFrameTime(
+                monotonicFrameBeginTime,
+                std::numeric_limits<double>::infinity(),
+                monotonicFrameBeginTime,
+                monotonicFrameBeginTime + 0.016666));
+    }
+    virtual void animate(WebFrameTime frameTime) { }
 
     // Called to layout the WebWidget. This MUST be called before Paint,
     // and it may result in calls to WebWidgetClient::didInvalidateRect.