SF: Add colorTransform to DisplayInfo

Adds the colorTransform field, which defines a vendor-specific color
transform (e.g., wide gamut, sRGB, etc.) to the DisplayInfo class, and
populates it from the HWC interface.

Bug: 20853317
Change-Id: I153edc36a361407656f3eb5082b96c2da2ecbec7
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.h b/services/surfaceflinger/DisplayHardware/HWComposer.h
index cc98b4c..5e0b3d8 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.h
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.h
@@ -257,6 +257,7 @@
         float xdpi;
         float ydpi;
         nsecs_t refresh;
+        int colorTransform;
     };
 
     // Query display parameters.  Pass in a display index (e.g.