Use the frame time from Choreographer for computeScroll animation time.

ui/android/java/src/org/chromium/ui/base/WindowAndroid.java

Index: ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
diff --git a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
index 5d3d91326cd701a75dfa41a8b462b70004fbc8b8..411af89424dae6797976bd80b7a4ec44d5e6bc8c 100644
--- a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
+++ b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
@@ -155,6 +155,15 @@ public class WindowAndroid {
     }
 
     /**
+     * @return the last VSync frame time in milli seconds.
+     *
+     * @see org.chromium.ui.VSyncMonitor#getCurrentFrameTimeMillis()
+     */
+    public long getCurrentFrameTimeMillis() {
+        return mVSyncMonitor.getCurrentFrameTimeMillis();
+    }
+
+    /**
      * @param context The application context.
      */
     @SuppressLint("UseSparseArrays")