Plumb an overscroll callback form the compositor to the Android UI thread.

android_webview/javatests/src/org/chromium/android_webview/test/AwTestContainerView.java

Index: android_webview/javatests/src/org/chromium/android_webview/test/AwTestContainerView.java
diff --git a/android_webview/javatests/src/org/chromium/android_webview/test/AwTestContainerView.java b/android_webview/javatests/src/org/chromium/android_webview/test/AwTestContainerView.java
index dbb28519d959408c3056dc309f69387c7edb2af9..88019c25dc55314e78383269f2ea63cd0c92d9a6 100644
--- a/android_webview/javatests/src/org/chromium/android_webview/test/AwTestContainerView.java
+++ b/android_webview/javatests/src/org/chromium/android_webview/test/AwTestContainerView.java
@@ -155,5 +155,9 @@ class AwTestContainerView extends FrameLayout {
         public void setMeasuredDimension(int measuredWidth, int measuredHeight) {
             AwTestContainerView.super.setMeasuredDimension(measuredWidth, measuredHeight);
         }
+
+        @Override
+        public void onOverScroll(int deltaX, int deltaY) {
+        }
     }
 }