Delete IsAtLeastOS10_9() and IsAtMostOS10_9()

chrome/browser/ui/cocoa/browser_window_controller_private.mm

 // Copyright (c) 2012 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 "chrome/browser/ui/cocoa/browser_window_controller_private.h"
 
 #include <cmath>
 
 #import "base/auto_reset.h"
 #include "base/command_line.h"
@@ skipping 1096 matching lines @@
   // Add in the subviews above the tabContentArea.
   for (NSUInteger i = index + 1; i < [subviews count]; ++i) {
     NSView* view = [subviews objectAtIndex:i];
     [self.chromeContentView addSubview:view
                             positioned:NSWindowAbove
                             relativeTo:nil];
   }
 }
 
 + (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];
 }
 
 - (BOOL)shouldUseMavericksAppKitFullscreenHack {
   if (![[self class] systemSettingsRequireMavericksAppKitFullscreenHack])
     return NO;
   if (!enteringAppKitFullscreen_)
     return NO;
   if (enteringAppKitFullscreenOnPrimaryScreen_)
     return NO;
 
   return YES;
 }
 
 - (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];
   if (!root.layer)
     return NO;
 
   // AppKit on OSX 10.9 has a bug for applications linked against OSX 10.8 SDK
   // and earlier. Under specific circumstances, it prevents the custom AppKit
   // transition from working well. See http://crbug.com/396980 for more
   // details.
@@ skipping 119 matching lines @@
   if (fullscreenLowPowerCoordinator_)
     fullscreenLowPowerCoordinator_->SetHasActiveSheet(false);
 }
 
 - (void)childWindowsDidChange {
   if (fullscreenLowPowerCoordinator_)
     fullscreenLowPowerCoordinator_->ChildWindowsChanged();
 }
 
 @end  // @implementation BrowserWindowController(Private)