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

chrome/browser/ui/cocoa/image_button_cell.mm

 // Copyright (c) 2011 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.
 
 #import "chrome/browser/ui/cocoa/image_button_cell.h"
 
 #include "base/logging.h"
 #import "chrome/browser/themes/theme_service.h"
 #import "chrome/browser/ui/cocoa/image_utils.h"
 #import "chrome/browser/ui/cocoa/themed_window.h"
@@ skipping 120 matching lines @@
   ui::ThemeProvider* themeProvider = [[controlView window] themeProvider];
   if (!themeProvider)
     return nil;
 
   return themeProvider->GetNSImageNamed(imageID, true);
 }
 
 - (void)setIsMouseInside:(BOOL)isMouseInside {
   if (isMouseInside_ != isMouseInside) {
     isMouseInside_ = isMouseInside;
-    [[self controlView] setNeedsDisplay:YES];
+    NSView<ImageButton>* control =
+        static_cast<NSView<ImageButton>*>([self controlView]);
+    if ([control respondsToSelector:@selector(mouseInsideStateDidChange:)]) {
+      [control mouseInsideStateDidChange:isMouseInside];
+    }
+    [control setNeedsDisplay:YES];
   }
 }
 
+- (void)setShowsBorderOnlyWhileMouseInside:(BOOL)show {
+  VLOG_IF(1, !show) << "setShowsBorderOnlyWhileMouseInside:NO ignored";
+}
+
+- (BOOL)showsBorderOnlyWhileMouseInside {
+  // Always returns YES so that buttons always get mouse tracking even when
+  // disabled. The reload button (and possibly others) depend on this.
+  return YES;
+}
+
 - (void)mouseEntered:(NSEvent*)theEvent {
   [self setIsMouseInside:YES];
 }
 
 - (void)mouseExited:(NSEvent*)theEvent {
   [self setIsMouseInside:NO];
 }
 
 @end