Enable AutoResize for Constrained Web Dialogs for Mac.

chrome/browser/ui/cocoa/constrained_window/constrained_window_sheet_controller_unittest.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/ui/cocoa/constrained_window/constrained_window_sheet_controller.h"
 
 #import "chrome/browser/ui/cocoa/cocoa_test_helper.h"
 #import "chrome/browser/ui/cocoa/constrained_window/constrained_window_custom_sheet.h"
 #import "testing/gtest_mac.h"
 
@@ skipping 38 matching lines @@
 
 - (void)pulseSheet {
 }
 
 - (void)makeSheetKeyAndOrderFront {
 }
 
 - (void)updateSheetPosition {
 }
 
+- (void)resizeWithNewSize:(NSSize)size {
+  // NOOP
+}
+
 - (NSWindow*)sheetWindow {
   return [alert_ window];
 }
 
 - (void)alertDidEnd:(NSAlert *)alert
          returnCode:(NSInteger)returnCode
             ctxInfo:(void *)contextInfo {
   returnCode_ = returnCode;
 }
 
@@ skipping 234 matching lines @@
   [system_sheet setAlert:alert];
 
   EXPECT_FALSE([[alert window] isVisible]);
   [controller_ showSheet:system_sheet forParentView:active_tab_view_];
   EXPECT_TRUE([[alert window] isVisible]);
 
   [controller_ closeSheet:system_sheet];
   EXPECT_FALSE([[alert window] isVisible]);
   EXPECT_EQ(kSystemSheetReturnCode, [system_sheet returnCode]);
 }