Check if there is a SW controlling the start page for app banner.

content/public/browser/service_worker_context.h

Index: content/public/browser/service_worker_context.h
diff --git a/content/public/browser/service_worker_context.h b/content/public/browser/service_worker_context.h
index 22c989b4ce8254ddfd423421af59aec9cec2f69c..ae05d98a527f7a2cf64ee404e82a2ab0da15a449 100644
--- a/content/public/browser/service_worker_context.h
+++ b/content/public/browser/service_worker_context.h
@@ -32,6 +32,9 @@ class ServiceWorkerContext {
   typedef base::Callback<void(const std::vector<ServiceWorkerUsageInfo>&
                                   usage_info)> GetUsageInfoCallback;
 
+  typedef base::Callback<void(bool has_same_service_worker)>
+      CheckHasSameServiceWorkerCallback;
+
   // Registers the header name which should not be passed to the ServiceWorker.
   // Must be called from the IO thread.
   CONTENT_EXPORT static void AddExcludedHeadersForFetchEvent(
@@ -73,7 +76,7 @@ class ServiceWorkerContext {
 
   // TODO(jyasskin): Provide a way to SendMessage to a Scope.
 
-  // Determines if a request for 'url' can be satisfied while offline.
+  // Determines if a request for |url| can be satisfied while offline.
   // This method always completes asynchronously.
   virtual void CanHandleMainResourceOffline(const GURL& url,
                                             const GURL& first_party,
@@ -84,6 +87,13 @@ class ServiceWorkerContext {
   virtual void GetAllOriginsInfo(const GetUsageInfoCallback& callback) = 0;
   virtual void DeleteForOrigin(const GURL& origin_url) = 0;
 
+  // Determines if an active Service Worker registration exists that matches
+  // |url|, and if the same registration also matches |other_url|.
+  virtual void CheckHasSameServiceWorker(

[falken, 2015/02/05 15:46:46]

This name is a bit off since it's only checking whether |other_url| falls inside
the scope of |url|'s registration (regardless of whether |other_url|'s
registration may be different). Can you rename to "CheckHasServiceWorker" and in
the comment explain that it determines whether there exists a registration that
matches |url| and additionally |other_url| falls inside the scope of that
registration (although it may have a longer-matching registration)?

[benwells, 2015/02/05 17:45:08]

Done.

+      const GURL& url,
+      const GURL& other_url,
+      const CheckHasSameServiceWorkerCallback& callback) = 0;
+
  protected:
   ServiceWorkerContext() {}
   virtual ~ServiceWorkerContext() {}