invalidate the webview after pressing the IME 'next' button

fixes http://b/issue?id=2141013
diff --git a/core/java/android/webkit/WebTextView.java b/core/java/android/webkit/WebTextView.java
index 1a65ce8..d24a5ab 100644
--- a/core/java/android/webkit/WebTextView.java
+++ b/core/java/android/webkit/WebTextView.java
@@ -328,6 +328,7 @@
             // Since the cursor will no longer be in the same place as the
             // focus, set the focus controller back to inactive
             mWebView.setFocusControllerInactive();
+            mWebView.invalidate();
             mOkayForFocusNotToMatch = true;
             break;
         case EditorInfo.IME_ACTION_DONE: