mac: Use NSWidth() and friends in a few more places.

chrome/browser/ui/cocoa/image_button_cell.mm

Index: chrome/browser/ui/cocoa/image_button_cell.mm
diff --git a/chrome/browser/ui/cocoa/image_button_cell.mm b/chrome/browser/ui/cocoa/image_button_cell.mm
index bb81227123cacb13f1fc97b15415dde73a82832f..58f4180a5ce5e4eea71d6174954cab2434a41ea3 100644
--- a/chrome/browser/ui/cocoa/image_button_cell.mm
+++ b/chrome/browser/ui/cocoa/image_button_cell.mm
@@ -68,9 +68,9 @@ const CGFloat kImageNoFocusAlpha = 0.65;
   NSRect imageRect;
   imageRect.size = [image size];
   imageRect.origin.x = cellFrame.origin.x +
-    roundf((cellFrame.size.width - imageRect.size.width) / 2.0);
+    roundf((NSWidth(cellFrame) - NSWidth(imageRect)) / 2.0);
   imageRect.origin.y = cellFrame.origin.y +
-    roundf((cellFrame.size.height - imageRect.size.height) / 2.0);
+    roundf((NSHeight(cellFrame) - NSHeight(imageRect)) / 2.0);
 
   [image drawInRect:imageRect
            fromRect:NSZeroRect
@@ -83,7 +83,7 @@ const CGFloat kImageNoFocusAlpha = 0.65;
                                  controlView:controlView];
     NSRect overlayRect;
     overlayRect.size = [overlayImage size];
-    overlayRect.origin.x = NSMaxX(imageRect) - overlayRect.size.width +
+    overlayRect.origin.x = NSMaxX(imageRect) - NSWidth(overlayRect) +
                            kOverlayOffsetX;
     overlayRect.origin.y = NSMinY(imageRect) + kOverlayOffsetY;