libgui: Add a test for SRGB surfaces

Add SRGBTest.RenderToSRGBSurface, which validates that passing the
SRGB colorspace attributes to eglCreateWindowSurface actually
results in an SRGB surface by comparing the output values to those
of a standard RGB surface.

Change-Id: I3d5fef8070ed8fa2357ddd1c5fcc849ae3fbd12a
diff --git a/libs/ui/PixelFormat.cpp b/libs/ui/PixelFormat.cpp
index d2d103a..5ce7fba 100644
--- a/libs/ui/PixelFormat.cpp
+++ b/libs/ui/PixelFormat.cpp
@@ -26,6 +26,8 @@
         case PIXEL_FORMAT_RGBA_8888:
         case PIXEL_FORMAT_RGBX_8888:
         case PIXEL_FORMAT_BGRA_8888:
+        case PIXEL_FORMAT_sRGB_A_8888:
+        case PIXEL_FORMAT_sRGB_X_8888:
             return 4;
         case PIXEL_FORMAT_RGB_888:
             return 3;