Enhanced frame profiling from gfxinfo

You can now set the max number of frames being tracked by the gfxinfo
profiling data by doing 'adb shell setprop hwui.profil.maxframes #'.
Also, running gfxinfo automatically resets the data so that any set of
frame data always starts from the beginning.

Change-Id: I87ae3fb4d580741a1b2fba75be4ec540de7c52a4