Update WebViewClient.shouldInterceptRequest JavaDoc.
Update WebViewClient.shouldInterceptRequest JavaDoc.

This changes the wording to say 'not UI thread' instead of 'network
thread'.

Change-Id: I9bc94830297b88639e7749392e3c2082b087f4ce

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