Allow cross dependencies between BCKSF and BSKSF

components/keyed_service/ios/browser_state_helper.cc

-// 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.
-
-#include "components/keyed_service/ios/browser_state_helper.h"
-
-#include "base/logging.h"
-#include "base/supports_user_data.h"
-#include "ios/web/public/browser_state.h"
-
-// iOS code is still using BrowserContextKeyedServiceFactory and until the
-// upstreaming is complete (http://crbug.com/419366) there is need to have
-// mixed dependency between BCKSF and BSKSF.
-//
-// The implementation has BrowserStateKeyedServiceFactory supporting a
-// BrowserContextDependencyManager as DependencyManager. Thus the context
-// parameter passed to the BrowserStateKeyedServiceFactory can either be
-// content::BrowserContext if the method is invoked by DependencyManager
-// or web::BrowserState if the method is invoked via the type-safe public
-// API.
-//
-// The public API of BrowserStateKeyedServiceFactory is type-safe (all
-// public method receive web::BrowserState for context object), so only
-// methods that take a base::SupportsUserData need to discriminate
-// between the two objects.
-//
-// If the base::SupportsUserData is a web::BrowserState then the public
-// method web::BrowserState::FromSupportsUserData can do the conversion
-// safely. If this method fails then context is content::BrowserContext
-// and the methods defined below allow the embedder to provides helper
-// to find the associated web::BrowserState (there is a 1:1 mapping).
-
-namespace {
-BrowserStateFromContextFn g_browser_state_from_context = nullptr;
-}  // namespace
-
-void SetBrowserStateFromContextHelper(BrowserStateFromContextFn helper) {
-  g_browser_state_from_context = helper;
-}
-
-web::BrowserState* BrowserStateFromContext(base::SupportsUserData* context) {
-  web::BrowserState* state = nullptr;
-  if (context) {
-    state = web::BrowserState::FromSupportsUserData(context);
-    if (!state && g_browser_state_from_context)
-      state = g_browser_state_from_context(context);
-    DCHECK(state) << "cannot convert context to web::BrowserState";
-  }
-  return state;
-}