Add a GDK_COLOR_RGB macro for constructing GdkColors.

base/gfx/gtk_util.h

Index: base/gfx/gtk_util.h
diff --git a/base/gfx/gtk_util.h b/base/gfx/gtk_util.h
index bf6e6aa9f45f658a89261900c6e8c30d634f2009..40a7855505c7461903b5e94d9c1eb3b8773a89ae 100755
--- a/base/gfx/gtk_util.h
+++ b/base/gfx/gtk_util.h
@@ -11,6 +11,11 @@ typedef struct _GdkPixbuf GdkPixbuf;
 typedef struct _GdkRegion GdkRegion;
 class SkBitmap;
 
+// Define a macro for creating GdkColors from RGB values.  This is a macro to
+// allow static construction of literals, etc.  Use this like:
+//   GdkColor white = GDK_COLOR_RGB(0xff, 0xff, 0xff);
+#define GDK_COLOR_RGB(r, g, b) {0, r * 257, g * 257, b * 257}
+
 namespace gfx {
 
 class Rect;