Support fallback key events

 Bug: 6023055

Change-Id: Ifc36425d6b09d0938f7e08176a749159c27fe088
diff --git a/src/com/android/browser/Tab.java b/src/com/android/browser/Tab.java
index 04bee08..62f9548 100644
--- a/src/com/android/browser/Tab.java
+++ b/src/com/android/browser/Tab.java
@@ -895,7 +895,9 @@
             if (!mInForeground) {
                 return;
             }
-            mWebViewController.onUnhandledKeyEvent(event);
+            if (!mWebViewController.onUnhandledKeyEvent(event)) {
+                super.onUnhandledKeyEvent(view, event);
+            }
         }
 
         @Override