Finish zoomBy API hookup.

BUG: 13399510
diff --git a/chromium/java/com/android/webview/chromium/WebViewChromium.java b/chromium/java/com/android/webview/chromium/WebViewChromium.java
index b593f1f..b0167b1 100644
--- a/chromium/java/com/android/webview/chromium/WebViewChromium.java
+++ b/chromium/java/com/android/webview/chromium/WebViewChromium.java
@@ -1462,15 +1462,12 @@
         return mAwContents.zoomOut();
     }
 
-    //TODO: remove once frameworks/base is updated
-    //@Override
+    @Override
     public boolean zoomBy(float factor) {
         mFactory.startYourEngines(true);
         // This is an L API and therefore we can enforce stricter threading constraints.
         checkThread();
-        //TODO: remove once Chromium-side CL is merged.
-        //return mAwContents.zoomBy(factor);
-        return false;
+        return mAwContents.zoomBy(factor);
     }
 
     @Override