Add a Material Design Circular Activity Indicator (Spinner) view for Mac.

chrome/browser/ui/cocoa/spinner_view.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_UI_COCOA_SPINNER_VIEW_H_
+#define CHROME_BROWSER_UI_COCOA_SPINNER_VIEW_H_
+
+#import <Cocoa/Cocoa.h>
+
+#import "base/mac/scoped_nsobject.h"
+
+// A view that displays a Material Design Circular Activity Indicator (aka a
+// "spinner") for Mac Chrome. To use, create a SpinnerView of the desired size
+// and add to a view hierarchy. SpinnerView uses Core Animation to achieve GPU-
+// accelerated animation and smooth scaling to any size.
+@interface SpinnerView : NSView {
+ @private
+  bool isAnimating_;
+}
+
+@end
+
+#endif  // CHROME_BROWSER_UI_COCOA_SPINNER_VIEW_H_