add null check to copy selection
add null check to copy selection

This prevents a toast from appearing
if copyselection is done initially.

bug:3339016
Change-Id: If6f91b8f3794b3807fb3319fc542838abd431c64

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