Fix npe in getCacheTotalSize.
Fix npe in getCacheTotalSize.

Bug: 2882277
Change-Id: I9319a48e0ed75561d3d04691fb288f69d11edc84

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