Tweak NSUserActivity forward declaration

chrome/browser/app_controller_mac.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/app_controller_mac.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ skipping 1603 matching lines @@
           isEqualToString:NSUserActivityTypeBrowsingWeb]) {
     return NO;
   }
 
   NSString* originString = base::mac::ObjCCast<NSString>(
       [userActivity.userInfo objectForKey:handoff::kOriginKey]);
   handoff::Origin origin = handoff::OriginFromString(originString);
   UMA_HISTOGRAM_ENUMERATION(
       "OSX.Handoff.Origin", origin, handoff::ORIGIN_COUNT);
 
-  NSURL* url = userActivity.webPageURL;
+  NSURL* url = userActivity.webpageURL;
   if (!url)
     return NO;
 
   GURL gurl(base::SysNSStringToUTF8([url absoluteString]));
   std::vector<GURL> gurlVector;
   gurlVector.push_back(gurl);
 
   [self openUrlsReplacingNTP:gurlVector];
   return YES;
 }
 
 - (void)application:(NSApplication*)application
     didFailToContinueUserActivityWithType:(NSString*)userActivityType
                                     error:(NSError*)error {
 }
 
 @end  // @implementation AppController
 
 //---------------------------------------------------------------------------
 
 namespace app_controller_mac {
 
 bool IsOpeningNewWindow() {
   return g_is_opening_new_window;
 }
 
 }  // namespace app_controller_mac