[MacViews] Implement colored window frames.

ui/gfx/mac/nswindow_frame_controls.h

Index: ui/gfx/mac/nswindow_frame_controls.h
diff --git a/ui/gfx/mac/nswindow_frame_controls.h b/ui/gfx/mac/nswindow_frame_controls.h
index 7ec7ab7ee0f6b7aecb549f422c51682a4d218c55..6239a242aa7b19abd8955e8b3e9215ad56a90a11 100644
--- a/ui/gfx/mac/nswindow_frame_controls.h
+++ b/ui/gfx/mac/nswindow_frame_controls.h
@@ -5,12 +5,22 @@
 #ifndef UI_GFX_MAC_NSWINDOW_FRAME_CONTROLS_H_
 #define UI_GFX_MAC_NSWINDOW_FRAME_CONTROLS_H_
 
-#include "ui/gfx/gfx_export.h"
+#import <Cocoa/Cocoa.h>
 
-@class NSWindow;
+#include "base/mac/scoped_nsobject.h"
+#include "third_party/skia/include/core/SkColor.h"
+#include "ui/gfx/gfx_export.h"
 
-namespace gfx {
+// A view that paints a solid color. Used to change the title bar background.
+GFX_EXPORT @interface TitlebarBackgroundView : NSView {
+ @private
+  base::scoped_nsobject<NSColor> color_;
+  base::scoped_nsobject<NSColor> inactiveColor_;
+}
+- (void)setColor:(NSColor*)color inactiveColor:(NSColor*)inactiveColor;
+@end
 
+    namespace gfx {
 class Size;
 
 // Set whether the window can be fullscreened.
@@ -26,6 +36,10 @@ GFX_EXPORT void ApplyNSWindowSizeConstraints(NSWindow* window,
                                              bool can_resize,
                                              bool can_fullscreen);
 
+// Adds a TitlebarBackgroundView to the [[window contentView] superView].
+GFX_EXPORT void AddColoredTitlebarToNSWindow(

[jackhou1, 2015/04/24 07:05:03]

Should we merge TitlebarBackgroundView and TabStripBackgroundView?

[tapted, 2015/05/06 02:58:29]

I'd lean towards "nah" - probably not enough in common - just an NSBezierPath.

The common bit might be
`gfx::ClipCurrentDrawingContextToRoundedWindow(NSWindow*)`, but there's too many
temporaries needed later

+    NSWindow * window, SkColor active_color, SkColor inactive_color);
+
 }  // namespace gfx
 
 #endif  // UI_GFX_MAC_NSWINDOW_FRAME_CONTROLS_H_