Refactor getInstalledRelatedApps code and add manifest logic and tests.

third_party/WebKit/public/platform/modules/installedapp/WebRelatedAppsFetcher.h

-// Copyright 2016 The Chromium Authors. All rights reserved.
+// Copyright 2017 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.
 
-#ifndef WebInstalledAppClient_h
-#define WebInstalledAppClient_h
+#ifndef WebRelatedAppsFetcher_h
+#define WebRelatedAppsFetcher_h
 
 #include "public/platform/WebCallbacks.h"
 #include "public/platform/WebSecurityOrigin.h"
 #include "public/platform/WebVector.h"
 #include "public/platform/modules/installedapp/WebRelatedApplication.h"
 
+#include <memory>
+
 namespace blink {
 
 using AppInstalledCallbacks =
     WebCallbacks<const WebVector<WebRelatedApplication>&, void>;
 
-class WebInstalledAppClient {
+class WebRelatedAppsFetcher {
  public:
-  virtual ~WebInstalledAppClient() {}
+  virtual ~WebRelatedAppsFetcher() {}
 
-  // Takes ownership of the AppInstalledCallbacks.
-  virtual void getInstalledRelatedApps(
-      const WebSecurityOrigin&,
+  // Gets the list of related applications from the web frame's manifest.
+  virtual void getManifestRelatedApplications(
       std::unique_ptr<AppInstalledCallbacks>) = 0;
 };
 
 }  // namespace blink
 
-#endif  // WebInstalledAppClient_h
+#endif  // WebRelatedAppsFetcher_h