SF: User buffer size to compute crop, set geometry and update cursor pos

Simplify compute initial crop logic to use computeBounds

Bug:114413815
Test: go/wm-smoke
Test: manual test with cursor on buffer and color layer
Test: mmma frameworks/native/services/surfaceflinger/tests/ && \
mmma frameworks/native/libs/gui/tests/ && adb sync data && \
adb shell /data/nativetest64/libgui_test/libgui_test && \
adb shell /data/nativetest64/libsurfaceflinger_unittest/libsurfaceflinger_unittest && \
adb shell /data/nativetest64/SurfaceFlinger_test/SurfaceFlinger_test && \
adb shell /data/nativetest64/SurfaceParcelable_test/SurfaceParcelable_test && \
echo "ALL TESTS PASSED"

Change-Id: I8dbdfcf77e4b23e057e3fd748877b89bedb02939