[Mac] Refactor the fullscreen menubar

ui/base/cocoa/appkit_utils.mm

 // Copyright 2013 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 "ui/base/cocoa/appkit_utils.h"
 
+#include <cmath>
+
 #include "base/mac/mac_util.h"
 #include "ui/base/resource/resource_bundle.h"
 
 namespace {
 
 // Double-click in window title bar actions.
 enum class DoubleClickAction {
   NONE,
   MINIMIZE,
   MAXIMIZE,
@@ skipping 85 matching lines @@
       break;
   }
 }
 
 bool ForceClickInvokesQuickLook() {
   return [[NSUserDefaults standardUserDefaults]
              integerForKey:@"com.apple.trackpad.forceClick"] ==
          static_cast<NSInteger>(ForceTouchAction::QUICK_LOOK);
 }
 
+bool IsCGFloatEqual(CGFloat a, CGFloat b) {
+  return std::fabs(a - b) <= std::numeric_limits<CGFloat>::epsilon();
+}
+
 }  // namespace ui