Make scrollAnimatorEnabled work on Mac like it does on other platforms

base/mac/mac_util.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.
 
 #include "base/mac/mac_util.h"
 
 #import <Cocoa/Cocoa.h>
 #import <IOKit/IOKitLib.h>
 #include <errno.h>
 #include <stddef.h>
 #include <string.h>
 #include <sys/utsname.h>
 #include <sys/xattr.h>
 
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/mac/bundle_locations.h"
 #include "base/mac/foundation_util.h"
 #include "base/mac/mac_logging.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/mac/scoped_ioobject.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/mac/sdk_forward_declarations.h"
+#include "base/message_loop/message_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/sys_string_conversions.h"
 
 namespace base {
 namespace mac {
 
 namespace {
 
 // The current count of outstanding requests for full screen mode from browser
@@ skipping 562 matching lines @@
           StringPiece(begin + number_loc, begin + comma_loc), &major_tmp) ||
       !StringToInt(
           StringPiece(begin + comma_loc + 1, ident.end()), &minor_tmp))
     return false;
   *type = ident.substr(0, number_loc);
   *major = major_tmp;
   *minor = minor_tmp;
   return true;
 }
 
+bool IsScrollAnimationEnabled() {

[Robert Sesek, 2016/02/08 17:39:51]

I don't think this needs to be in base, since it's only called in //ui/gfx. Just
create animation_mac.mm to implement ScrollAnimationsEnabledBySystem in an
ObjC++ file.

[bokan, 2016/02/08 20:55:06]

Done. I moved the Windows bits into animation_win.cc for consistency too.

+  // Because of sandboxing, OS settings should only be queried from the browser
+  // process.
+  DCHECK(base::MessageLoopForUI::IsCurrent() ||
+      base::MessageLoopForIO::IsCurrent());
+
+  bool enabled = false;
+  id value = nil;
+  if (base::mac::IsOSMountainLionOrLater()) {
+    value = [[NSUserDefaults standardUserDefaults]
+        objectForKey:@"NSScrollAnimationEnabled"];
+  } else {
+    value = [[NSUserDefaults standardUserDefaults]
+        objectForKey:@"AppleScrollAnimationEnabled"];
+  }
+  if (value)
+    enabled = [value boolValue];
+  return enabled;
+}
+
+
 }  // namespace mac
 }  // namespace base