Fix crash of ExtensionManagement in guest mode

The default BrowserContextKeyedServiceFactory::GetBrowserContextToUse() returns NULL for guest mode profile, overriding it to redirect to original profile.

BUG=411763
TBR=finnur@chromium.org

Review URL: https://codereview.chromium.org/550053003

Cr-Commit-Position: refs/heads/master@{#293729}

chrome/browser/extensions/extension_management.cc

@@ -10,6 +10,7 @@
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/extensions/external_provider_impl.h"
 #include "chrome/browser/extensions/standard_management_policy_provider.h"
+#include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/profiles/profile.h"
 #include "components/crx_file/id_util.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
@@ -250,4 +251,9 @@ KeyedService* ExtensionManagementFactory::BuildServiceInstanceFor(
       Profile::FromBrowserContext(context)->GetPrefs());
 }
 
+content::BrowserContext* ExtensionManagementFactory::GetBrowserContextToUse(
+    content::BrowserContext* context) const {
+  return chrome::GetBrowserContextRedirectedInIncognito(context);
+}
+
 }  // namespace extensions

chrome/browser/extensions/extension_management.h

@@ -180,6 +180,8 @@ class ExtensionManagementFactory : public BrowserContextKeyedServiceFactory {
   // BrowserContextKeyedServiceExtensionManagementFactory:
   virtual KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* context) const OVERRIDE;
+  virtual content::BrowserContext* GetBrowserContextToUse(
+      content::BrowserContext* context) const OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionManagementFactory);
 };