Fix one and hide the other warnings from core/jni

Most of the warnings are unused parameter from skia functions.
Cherry-picked from AOSP:https://android-review.googlesource.com/#/c/72224/

Change-Id: I9df57718d117c26b96163f751ccb056ca86ac072
Merge "Fix one and hide the other warnings from core/jni" into cm-11.0
Merge branch 'cm-11.0' of git://github.com/CyanogenMod/android_frameworks_base into cd-4.4