[Mac][Material Design] Bring bookmark hover background up to spec.

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 33333b832785b60f3951e3975ee5ceda73ecaf20..9bf413e21bb74a894963fecd8c51e1527e27b28a 100644
--- a/chrome/browser/ui/cocoa/gradient_button_cell.mm
+++ b/chrome/browser/ui/cocoa/gradient_button_cell.mm
@@ -546,6 +546,12 @@ 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;
+    }
+
     *returnInnerPath = [NSBezierPath bezierPathWithRoundedRect:drawFrame
                                                        xRadius:cornerRadius
                                                        yRadius:cornerRadius];