This patch improves the way that GuestViewManager tracks the destruction of GuestView embedders.

extensions/browser/browser_context_keyed_api_factory.h

Index: extensions/browser/browser_context_keyed_api_factory.h
diff --git a/extensions/browser/browser_context_keyed_api_factory.h b/extensions/browser/browser_context_keyed_api_factory.h
index fc0add240e066d5b81ea510ee7b1d2e4d44872b4..daafe3c317c8a962517d3257d4414f860d4ba0ee 100644
--- a/extensions/browser/browser_context_keyed_api_factory.h
+++ b/extensions/browser/browser_context_keyed_api_factory.h
@@ -76,6 +76,11 @@ class BrowserContextKeyedAPIFactory : public BrowserContextKeyedServiceFactory {
         T::GetFactoryInstance()->GetServiceForBrowserContext(context, true));
   }
 
+  static T* Get(content::BrowserContext* context, bool create) {

[not at google - send to devlin, 2015/07/20 21:17:57]

I'd rather a method like "GetIfExists" in addition to "Get", rather than having
a method which may or may not have a side-effect based on a boolean value it
gets passed.

Other than that, lgtm.

+    return static_cast<T*>(
+        T::GetFactoryInstance()->GetServiceForBrowserContext(context, create));
+  }
+
   // Declare dependencies on other factories.
   // By default, ExtensionSystemFactory is the only dependency; however,
   // specializations can override this. Declare your specialization in