base::mac::IsOSSierra() -> base::mac::IsOS10_12(), etc.

chrome/browser/ui/cocoa/browser_window_fullscreen_transition.mm

 // Copyright 2015 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_fullscreen_transition.h"
 
 #include <QuartzCore/QuartzCore.h>
 
 #include <memory>
 
@@ skipping 221 matching lines @@
   [self takeSnapshot];
   [self makeAndPrepareSnapshotWindow];
   return @[ primaryWindow_.get(), snapshotWindow_.get() ];
 }
 
 - (BOOL)isTransitionCompleted {
   return completedTransition_;
 }
 
 - (void)startCustomFullScreenAnimationWithDuration:(NSTimeInterval)duration {
-  CGFloat durationFraction = base::mac::IsOSYosemite()
+  CGFloat durationFraction = base::mac::IsOS10_10()
                                  ? kAnimationDurationFractionYosemite
                                  : kAnimationDurationFraction;
   CGFloat animationDuration = duration * durationFraction;
   [self preparePrimaryWindowForAnimation];
   [self animatePrimaryWindowWithDuration:animationDuration];
   [self animateSnapshotWindowWithDuration:animationDuration];
 }
 
 - (BOOL)shouldWindowBeUnconstrained {
   return changingPrimaryWindowSize_;
@@ skipping 297 matching lines @@
   return [[[window contentView] superview] layer];
 }
 
 - (NSPoint)pointRelativeToCurrentScreen:(NSPoint)point {
   NSRect screenFrame = [[primaryWindow_ screen] frame];
   return NSMakePoint(point.x - screenFrame.origin.x,
                      point.y - screenFrame.origin.y);
 }
 
 @end