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
+// conversion is complete (http://crbug.com/478763) 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;
+UnderlyingContextFromContextFn g_underlying_context_from_context = nullptr;
+OriginalContextFromContextFn g_original_context_from_context = nullptr;
 }  // namespace
 
-void SetBrowserStateFromContextHelper(BrowserStateFromContextFn helper) {
-  g_browser_state_from_context = helper;
+void SetUnderlyingContextFromContextHelper(
+    UnderlyingContextFromContextFn helper) {
+  DCHECK_NE(UnderlyingContextFromContext, helper);
+  g_underlying_context_from_context = helper;
 }
 
-web::BrowserState* BrowserStateFromContext(base::SupportsUserData* context) {
-  web::BrowserState* state = nullptr;
+web::BrowserState* UnderlyingContextFromContext(
+    base::SupportsUserData* context) {
+  web::BrowserState* underlying_context = 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";
+    underlying_context = web::BrowserState::FromSupportsUserData(context);
+    if (!underlying_context && g_underlying_context_from_context)
+      underlying_context = g_underlying_context_from_context(context);
+    DCHECK(underlying_context) << "cannot resolve underlying context";
   }
-  return state;
+  return underlying_context;
 }
+
+void SetOriginalContextFromContextHelper(OriginalContextFromContextFn helper) {
+  g_original_context_from_context = helper;
+}
+
+base::SupportsUserData* OriginalContextFromContext(
+    base::SupportsUserData* context) {
+  base::SupportsUserData* original_context = context;
+  if (context) {
+    web::BrowserState* browser_state =
+        web::BrowserState::FromSupportsUserData(context);
+    if (browser_state && g_original_context_from_context)
+      original_context = g_original_context_from_context(browser_state);
+  }
+  return original_context;
+}