Track where WebContents are created in order to better understand issue.

chrome/browser/ui/cocoa/profiles/profile_chooser_controller.mm

 // Copyright 2014 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/profiles/profile_chooser_controller.h"
 
 #import <Carbon/Carbon.h>  // kVK_Return.
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/bundle_locations.h"
@@ skipping 37 matching lines @@
 #include "chrome/common/url_constants.h"
 #include "chrome/grit/chromium_strings.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/signin/core/browser/profile_oauth2_token_service.h"
 #include "components/signin/core/browser/signin_manager.h"
 #include "components/signin/core/common/profile_management_switches.h"
 #include "content/public/browser/native_web_keyboard_event.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_source.h"
 #include "google_apis/gaia/oauth2_token_service.h"
 #include "grit/theme_resources.h"
 #include "skia/ext/skia_utils_mac.h"
 #import "third_party/google_toolbox_for_mac/src/AppKit/GTMUILocalizerAndLayoutTweaker.h"
 #import "ui/base/cocoa/cocoa_base_utils.h"
 #import "ui/base/cocoa/controls/blue_label_button.h"
 #import "ui/base/cocoa/controls/hyperlink_button_cell.h"
 #import "ui/base/cocoa/controls/hyperlink_text_view.h"
 #import "ui/base/cocoa/hover_image_button.h"
 #include "ui/base/cocoa/window_size_constants.h"
@@ skipping 2027 matching lines @@
           browser_->profile(), GetAuthErrorAccountId(browser_->profile()));
       messageId = IDS_PROFILES_GAIA_REAUTH_TITLE;
       break;
     default:
       NOTREACHED() << "Called with invalid mode=" << viewMode_;
       break;
   }
 
   webContents_.reset(content::WebContents::Create(
       content::WebContents::CreateParams(browser_->profile())));
+  WebContentsSource::CreateForWebContentsAndLocation(webContents_.get(),
+                                                     FROM_HERE);
 
   webContentsDelegate_.reset(new GaiaWebContentsDelegate());
   webContents_->SetDelegate(webContentsDelegate_.get());
   webContents_->GetController().LoadURL(url,
                                         content::Referrer(),
                                         ui::PAGE_TRANSITION_AUTO_TOPLEVEL,
                                         std::string());
   NSView* webview = webContents_->GetNativeView();
   [webview setFrameSize:NSMakeSize(kFixedGaiaViewWidth, kFixedGaiaViewHeight)];
   [container addSubview:webview];
@@ skipping 289 matching lines @@
 }
 
 - (bool)shouldShowGoIncognito {
   bool incognitoAvailable =
       IncognitoModePrefs::GetAvailability(browser_->profile()->GetPrefs()) !=
           IncognitoModePrefs::DISABLED;
   return incognitoAvailable && !browser_->profile()->IsGuestSession();
 }
 
 @end