check for webviewcore before reading settings
check for webviewcore before reading settings

In setActive(), the WebViewCore instance may
have already been destroyed before the settings
object can be read.

Change-Id: I46b2a57b2d92fc7216b1c984f7044fea1fc2409e
http://b/2570700

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