Frameworks/base: Mask Skia warning in GraphicsJNI

Do not allow unused-parameter warnings from Skia includes.

Change-Id: Icc765cb0eaf10cd566a64892fbfe7380143ccb42
Frameworks/base: Wall Werror in native/android

Turn on -Wall -Werror in native/android.

Change-Id: I28bab9ebd2fe3f6935878816773a04531e26450f