[Mac] Avoid "adding unknown subview" warning.

chrome/browser/ui/cocoa/full_size_content_window.mm

 // Copyright 2014 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/full_size_content_window.h"
 
 #include <crt_externs.h>
 
 #include "base/auto_reset.h"
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
+#include "base/mac/mac_util.h"
 #include "base/mac/scoped_objc_class_swizzler.h"
 
 @interface FullSizeContentWindow ()
 
 + (BOOL)shouldUseFullSizeContentViewForStyle:(NSUInteger)windowStyle;
 
 @end
 
 // This view always takes the size of its superview. It is intended to be used
 // as a NSWindow's contentView.  It is needed because NSWindow's implementation
@@ skipping 110 matching lines @@
   if (self) {
     if (wantsViewsOverTitlebar &&
         [FullSizeContentWindow
             shouldUseFullSizeContentViewForStyle:windowStyle]) {
       chromeWindowView_.reset([[FullSizeContentView alloc] init]);
       [chromeWindowView_
           setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
       [self setContentView:chromeWindowView_];
       [chromeWindowView_ setFrame:[[chromeWindowView_ superview] bounds]];
 
-      // Our content view overlaps the window control buttons, so we must ensure
-      // it is positioned below the buttons.
-      NSView* superview = [chromeWindowView_ superview];
-      [chromeWindowView_ removeFromSuperview];
+      if (base::mac::IsAtMostOS10_10()) {
+        // Our content view overlaps the window control buttons, so we must
+        // ensureit is positioned below the buttons.

[erikchen, 2016/09/20 23:07:47]

s/ensureit/ensure it/

[shrike, 2016/09/20 23:27:17]

Done.

+        NSView* superview = [chromeWindowView_ superview];
+        [chromeWindowView_ removeFromSuperview];
 
-      // Prevent the AppKit from generating a backtrace to include in it's
-      // complaint about our upcoming call to addSubview:positioned:relativeTo:.
-      // See +load for more info.
-      base::AutoReset<bool> disable_symbolication(&g_disable_callstacksymbols,
-                                                  true);
+        // Prevent the AppKit from generating a backtrace to include in it's
+        // complaint about our upcoming call to
+        // addSubview:positioned:relativeTo:. See +load for more info.
+        base::AutoReset<bool> disable_symbolication(&g_disable_callstacksymbols,
+                                                    true);
 
-      [superview addSubview:chromeWindowView_
-                 positioned:NSWindowBelow
+        [superview addSubview:chromeWindowView_
+                   positioned:NSWindowBelow
                  relativeTo:nil];
+      }
     }
   }
   return self;
 }
 
 - (void)forceContentViewFrame:(NSRect)frame {
   if ([chromeWindowView_ isKindOfClass:[FullSizeContentView class]]) {
     FullSizeContentView* contentView =
         base::mac::ObjCCast<FullSizeContentView>(chromeWindowView_);
     [contentView forceFrame:frame];
@@ skipping 30 matching lines @@
   return [super contentRectForFrameRect:fRect styleMask:aStyle];
 }
 
 - (NSRect)contentRectForFrameRect:(NSRect)frameRect {
   if (chromeWindowView_)
     return frameRect;
   return [super contentRectForFrameRect:frameRect];
 }
 
 @end