SF/HWC2: Add support for color transforms

Adds support for color transforms using the setColorTransform method
of HWC2.

This means that instead of always falling back to client composition
when applying a transform, SurfaceFlinger will allow the device to
make that decision. If all layers fall back to client composition, the
SKIP_CLIENT_COLOR_TRANSFORM capability allows the device greater
control over whether SF should apply the transform or whether it
should allow the device to apply it to the client target buffer.

Bug: 19539930
Change-Id: I47a3d5453a3c47a8dd105ab77cce7f9c9687e925
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 0df39a4..f063aaf 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -527,8 +527,11 @@
      */
 
     Daltonizer mDaltonizer;
+#ifndef USE_HWC2
     bool mDaltonize;
+#endif
 
+    mat4 mPreviousColorMatrix;
     mat4 mColorMatrix;
     bool mHasColorMatrix;