invalidate the webview after pressing the IME 'next' button
invalidate the webview after pressing the IME 'next' button

fixes http://b/issue?id=2141013

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base