Enable AutoResize for Constrained Web Dialogs for Mac.

chrome/browser/ui/cocoa/web_contents_modal_dialog_manager_views_mac.mm

 // Copyright 2015 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/web_contents_modal_dialog_manager_views_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #import "base/mac/foundation_util.h"
 #import "chrome/browser/ui/cocoa/constrained_window/constrained_window_sheet.h"
@@ skipping 78 matching lines @@
 }
 
 - (void)updateSheetPosition {
   ConstrainedWindowSheetController* controller =
       [ConstrainedWindowSheetController controllerForSheet:self];
   NSPoint origin = [controller originForSheet:self
                                withWindowSize:[customWindow_ frame].size];
   [customWindow_ setFrameOrigin:origin];
 }
 
+- (void)resizeWithNewSize:(NSSize)size {
+  // NOOP
+}
+
 - (NSWindow*)sheetWindow {
   return customWindow_;
 }
 
 @end
 
 SingleWebContentsDialogManagerViewsMac::SingleWebContentsDialogManagerViewsMac(
     NSWindow* dialog,
     web_modal::SingleWebContentsDialogManagerDelegate* delegate)
     : delegate_(delegate), host_(nullptr) {
@@ skipping 75 matching lines @@
 
 void SingleWebContentsDialogManagerViewsMac::OnWidgetDestroying(
     views::Widget* widget) {
   // On Mac, this would only be reached if something called -[NSWindow close]
   // on the dialog without going through Widget::Close or CloseNow(). Since
   // dialogs have no titlebar, it won't come from the system. If something
   // internally calls -[NSWindow close] it might break lifetime assumptions
   // made by DialogDelegate.
   NOTREACHED();
 }