Add support for GL_CHROMIUM_flipy

Review URL: http://codereview.appspot.com/5413051/


git-svn-id: http://skia.googlecode.com/svn/trunk@2723 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/GrGLDefines.h b/include/gpu/GrGLDefines.h
index 94e7cb5..650646d 100644
--- a/include/gpu/GrGLDefines.h
+++ b/include/gpu/GrGLDefines.h
@@ -174,6 +174,7 @@
 #define GR_GL_COLOR_CLEAR_VALUE              0x0C22
 #define GR_GL_COLOR_WRITEMASK                0x0C23
 #define GR_GL_UNPACK_ALIGNMENT               0x0CF5
+#define GR_GL_UNPACK_FLIP_Y                  0x9240
 #define GR_GL_PACK_ALIGNMENT                 0x0D05
 #define GR_GL_MAX_TEXTURE_SIZE               0x0D33
 #define GR_GL_MAX_VIEWPORT_DIMS              0x0D3A