Clarify handling client certificates
Clarify handling client certificates

Bug: 21910771

Clarify handling client certificates when using a webview. This is a
documentation change only.

Change-Id: Ida78bd89aa8867c99b4b9e4433e342767e9bac0d

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