[Mac][Material Design] Add MD hover to bookmark items in menus.

chrome/browser/ui/cocoa/gradient_button_cell.mm

Index: chrome/browser/ui/cocoa/gradient_button_cell.mm
diff --git a/chrome/browser/ui/cocoa/gradient_button_cell.mm b/chrome/browser/ui/cocoa/gradient_button_cell.mm
index 9bf413e21bb74a894963fecd8c51e1527e27b28a..fd343289cf48e90ade5615f57be2021c6c1789a5 100644
--- a/chrome/browser/ui/cocoa/gradient_button_cell.mm
+++ b/chrome/browser/ui/cocoa/gradient_button_cell.mm
@@ -546,11 +546,8 @@ static const NSTimeInterval kAnimationContinuousCycleDuration = 0.4;
     *returnInnerFrame = innerFrame;
   if (returnInnerPath) {
     DCHECK(*returnInnerPath == nil);
-    // In Material Design on Retina, nudge the hover background by 1px.
-    if ([self tag] == kMaterialStandardButtonTypeWithLimitedClickFeedback &&
-        kLineWidth < 1) {
-      drawFrame.origin.y -= kLineWidth;
-    }
+    drawFrame.origin.y +=
+        [self hoverBackgroundVerticalOffsetInControlView:controlView];
 
     *returnInnerPath = [NSBezierPath bezierPathWithRoundedRect:drawFrame
                                                        xRadius:cornerRadius
@@ -692,6 +689,10 @@ static const NSTimeInterval kAnimationContinuousCycleDuration = 0.4;
   return 1;
 }
 
+- (CGFloat)hoverBackgroundVerticalOffsetInControlView:(NSView*)controlView {
+  return 0.0;
+}
+
 // Overriden from NSButtonCell so we can display a nice fadeout effect for
 // button titles that overflow.
 // This method is copied in the most part from GTMFadeTruncatingTextFieldCell,