ActivityManager: memoize for performance

isHighEndGfx and isLargeRam are frequently called upon.. isLargeRam very
frequently within the ActivityStack. these aren't going to change after
they're calculated the first time so subject them to a basic memoization.
FTW.

Change-Id: I176089f99ac6c6e4074cb2fde502c729986ea701
change default for unknown sources & verify apps

Change-Id: I04467c0c1ef3985b416f6e58013ddc3ce4137712
build core/jni with fstrict

Change-Id: Ic2418b7b9a359a47ff8efc501c69b926c3c91c5a

Conflicts:
	core/jni/Android.mk
hwui: Fix build in ISO C++11 mode

Make sure log calls can't be confused with C++11 string literals

Change-Id: I1d458e92e690f6f2b922a05494db8c01da54e460
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>