Merge changes from topic "HWUI_JNI"

* changes:
  Export symbols for the newly exposed APEX/internal headers
  Remove dependence on libandroid_runtime from Bitmap.cpp
  Update Region.cpp to use AParcel NDK APIs
  Cleanup header and build targets for libhwui clients.
  Remove dependencies on headers outside UI module
  Cleanup LOG_TAG when bundled in HWUI
  Move android.graphics JNI & APEX files into HWUI