Delete IsAtLeastOS10_9() and IsAtMostOS10_9()

chrome/browser/ui/cocoa/browser_window_controller_private.mm

Index: chrome/browser/ui/cocoa/browser_window_controller_private.mm
diff --git a/chrome/browser/ui/cocoa/browser_window_controller_private.mm b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
index 36f13de383fb707a7e371ba3babf860741bda3a2..2c6df7b0f07b5af03db7fd5a43adf12e13235bba 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller_private.mm
+++ b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
@@ -1114,7 +1114,7 @@ willPositionSheet:(NSWindow*)sheet
 }
 
 + (BOOL)systemSettingsRequireMavericksAppKitFullscreenHack {
-  if (!base::mac::IsOS10_9())
+  if (base::mac::IsAtLeastOS10_10())

[Mark Mentovai, 2016/08/29 17:57:56]

I think that this kind of thing really was 10.9-specific (like not needed on
10.8 and not needed on 10.10), but since we don’t support those older OSes, I
guess it’s OK to fudge it.

     return NO;
   return [NSScreen respondsToSelector:@selector(screensHaveSeparateSpaces)] &&
          [NSScreen screensHaveSeparateSpaces];
@@ -1133,7 +1133,7 @@ willPositionSheet:(NSWindow*)sheet
 
 - (BOOL)shouldUseCustomAppKitFullscreenTransition:(BOOL)enterFullScreen {
   // Disable the custom exit animation in OSX 10.9: http://crbug.com/526327#c3.
-  if (base::mac::IsOS10_9() && !enterFullScreen)
+  if (!base::mac::IsAtLeastOS10_10() && !enterFullScreen)
     return NO;
 
   NSView* root = [[self.window contentView] superview];