[Mac] Refactor the fullscreen menubar

ui/base/cocoa/appkit_utils.mm

Index: ui/base/cocoa/appkit_utils.mm
diff --git a/ui/base/cocoa/appkit_utils.mm b/ui/base/cocoa/appkit_utils.mm
index 95483cfd284ed3bf61333d05c78ea3cd2b526d4d..6c3e7e2d9cbe5d68ddf091f92e580d30952e4bf1 100644
--- a/ui/base/cocoa/appkit_utils.mm
+++ b/ui/base/cocoa/appkit_utils.mm
@@ -4,6 +4,8 @@
 
 #import "ui/base/cocoa/appkit_utils.h"
 
+#include <cmath>
+
 #include "base/mac/mac_util.h"
 #include "ui/base/resource/resource_bundle.h"
 
@@ -109,4 +111,8 @@ bool ForceClickInvokesQuickLook() {
          static_cast<NSInteger>(ForceTouchAction::QUICK_LOOK);
 }
 
+bool IsCGFloatEqual(CGFloat a, CGFloat b) {
+  return std::fabs(a - b) <= std::numeric_limits<CGFloat>::epsilon();
+}
+
 }  // namespace ui