Fix up reload button to not flicker, and simplify implementation.

chrome/browser/ui/cocoa/image_button_cell.h

Index: chrome/browser/ui/cocoa/image_button_cell.h
diff --git a/chrome/browser/ui/cocoa/image_button_cell.h b/chrome/browser/ui/cocoa/image_button_cell.h
index c049294457448237eeb0e30831daa7d2a74bee01..07b5e089ac65ab055f0c7cd44698df3625e3a1f6 100644
--- a/chrome/browser/ui/cocoa/image_button_cell.h
+++ b/chrome/browser/ui/cocoa/image_button_cell.h
@@ -21,6 +21,13 @@ enum ButtonState {
 
 } // namespace ImageButtonCell
 
+@protocol ImageButton
+@optional
+// Sent from an ImageButtonCell to it's view when the button is enabled
+// and the mouse enters or exits the cell.

[Scott Hess - ex-Googler, 2011/07/21 00:48:40]

I don't think the comment is right WRT "enabled".  [The reload button
specifically tracks mouse-exit when disabled.]

[dmac, 2011/07/29 20:01:00]

Now it works when disabled as well.

+- (void)mouseInsideStateDidChange:(BOOL)isInside;
+@end
+
 // A button cell that can disable a different image for each possible button
 // state. Images are specified by image IDs.
 @interface ImageButtonCell : NSButtonCell {