Export a private webstore API to call into the new inline sign-in flow.

components/keyed_service/content/browser_context_keyed_service_factory.cc

Index: components/keyed_service/content/browser_context_keyed_service_factory.cc
diff --git a/components/keyed_service/content/browser_context_keyed_service_factory.cc b/components/keyed_service/content/browser_context_keyed_service_factory.cc
index f2180a6ec349edc27f7ffeb32046bffe5517b847..532e990f8806e40e212f46eb311de35c40958b9b 100644
--- a/components/keyed_service/content/browser_context_keyed_service_factory.cc
+++ b/components/keyed_service/content/browser_context_keyed_service_factory.cc
@@ -15,6 +15,11 @@
 void BrowserContextKeyedServiceFactory::SetTestingFactory(
     content::BrowserContext* context,
     TestingFactoryFunction testing_factory) {
+  if (!context) {
+    testing_factories_[NULL] = testing_factory;
+    return;
+  }
+
   // Destroying the context may cause us to lose data about whether |context|
   // has our preferences registered on it (since the context object itself
   // isn't dead). See if we need to readd it once we've gone through normal
@@ -77,10 +82,12 @@ KeyedService* BrowserContextKeyedServiceFactory::GetServiceForBrowserContext(
 
   // Create new object.
   // Check to see if we have a per-BrowserContext testing factory that we should
-  // use instead of default behavior.
+  // use instead of default behavior. Check for a global factory as well.
   KeyedService* service = NULL;
   BrowserContextOverriddenTestingFunctions::const_iterator jt =
       testing_factories_.find(context);
+  if (jt == testing_factories_.end())
+    jt = testing_factories_.find(NULL);
   if (jt != testing_factories_.end()) {
     if (jt->second) {
       if (!context->IsOffTheRecord())