mac: Only let two-finger-scrolling trigger history if web doesn't swallow gesture

chrome/browser/ui/cocoa/gesture_utils.mm

-// Copyright (c) 2011 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/gesture_utils.h"
-
-#include "base/mac/mac_util.h"
-
-namespace gesture_utils {
-
-BOOL RecognizeTwoFingerGestures() {
-  // Lion or higher will have support for two-finger swipe gestures.
-  if (!base::mac::IsOSLionOrLater())
-    return NO;
-
-  // A note about preferences:
-  // On Lion System Preferences, the swipe gesture behavior is controlled by the
-  // setting in Trackpad --> More Gestures --> Swipe between pages. This setting
-  // has three values:
-  //  A) Scroll left or right with two fingers. This should perform a cool
-  //     scrolling animation, but doesn't yet <http://crbug.com/90228>.
-  //  B) Swipe left or right with three fingers.
-  //  C) Swipe with two or three fingers.
-  //
-  // The three-finger gesture is controlled by the integer preference
-  // |com.apple.trackpad.threeFingerHorizSwipeGesture|. Its value is 0 for (A)
-  // and 1 for (B, C).
-  //
-  // The two-finger gesture is controlled by the preference below and is boolean
-  // YES for (A, C) and NO for (B).
-  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
-  [defaults synchronize];
-
-  // By default, the preference is not set. When it's not, the intrinsic Lion
-  // default (YES) should be returned.
-  NSDictionary* prefs = [defaults dictionaryRepresentation];
-  NSNumber* value = [prefs objectForKey:@"AppleEnableSwipeNavigateWithScrolls"];

[Mark Mentovai, 2011/08/15 14:43:57]

Buh-bye.

-  if (!value)
-    return YES;
-
-  // If the preference is set, return the value.
-  return [value boolValue];
-}
-
-// On Lion, returns YES if the scroll direction is "natural"/inverted. All other
-// OSes will return NO.
-BOOL IsScrollDirectionInverted() {
-  if (!base::mac::IsOSLionOrLater())
-    return NO;
-
-  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
-  [defaults synchronize];
-
-  // By default, the preference is not set. When it's not, the intrinsic Lion
-  // default (YES) should be returned.
-  NSDictionary* prefs = [defaults dictionaryRepresentation];
-  NSNumber* value = [prefs objectForKey:@"com.apple.swipescrolldirection"];
-  if (!value)
-    return YES;
-
-  return [value boolValue];
-}
-
-}  // namespace gesture_utils