[Mac] Refactor the fullscreen menubar

base/mac/mac_util.mm

Index: base/mac/mac_util.mm
diff --git a/base/mac/mac_util.mm b/base/mac/mac_util.mm
index 2f54b2799b5b01932b94fce98a63e5145ebae94b..35fe9d1444f85a487563de553474238ec3ffd93a 100644
--- a/base/mac/mac_util.mm
+++ b/base/mac/mac_util.mm
@@ -6,6 +6,8 @@
 
 #import <Cocoa/Cocoa.h>
 #import <IOKit/IOKitLib.h>
+
+#include <cmath>
 #include <errno.h>
 #include <stddef.h>
 #include <string.h>
@@ -173,6 +175,10 @@ CGColorSpaceRef GetSystemColorSpace() {
   return g_system_color_space;
 }
 
+bool IsCGFloatEqual(CGFloat a, CGFloat b) {
+  return std::fabs(a - b) <= std::numeric_limits<CGFloat>::epsilon();
+}
+
 // Add a request for full screen mode.  Must be called on the main thread.
 void RequestFullScreen(FullScreenMode mode) {
   DCHECK_LT(mode, kNumFullScreenModes);