Extract some stuff into PackageManager

mojo/shell/package_manager.h

+// Copyright 2015 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 MOJO_SHELL_PACKAGE_MANAGER_H_
+#define MOJO_SHELL_PACKAGE_MANAGER_H_
+
+#include "mojo/services/network/public/interfaces/url_loader.mojom.h"
+#include "mojo/shell/fetcher.h"
+
+class GURL;
+
+namespace mojo {
+namespace shell {
+
+class ApplicationManager;
+
+// A class implementing this interface assists Shell::ConnectToApplication in
+// resolving URLs and fetching the applications located therein.
+class PackageManager {
+ public:
+  PackageManager() {}
+  virtual ~PackageManager() {}
+
+  // Called once, during initialization, to tell the package manager about the
+  // associated ApplicationManager.
+  virtual void SetApplicationManager(ApplicationManager* manager) = 0;
+
+  // Resolves |url| to its canonical form. e.g. for mojo: urls, returns a file:
+  // url with a path ending in .mojo.
+  virtual GURL ResolveURL(const GURL& url) = 0;
+
+  // Asks the delegate to fetch the specified url. |url| must be unresolved,
+  // i.e. ResolveURL() above must not have been called on it.
+  // TODO(beng): figure out how not to expose Fetcher at all at this layer.
+  virtual void FetchRequest(
+      URLRequestPtr request,
+      const Fetcher::FetchCallback& loader_callback) = 0;
+
+  // Determine if a content handler should handle the response received by
+  // |fetcher|.
+  // |unresolved_url| is the url requested initially by a call to
+  // Shell::ConnectToApplication() before any resolution is applied.
+  // |task_runner| is a base::TaskRunner* that can be used to post callbacks.
+  // |new_response| is the response that should be passed to
+  // ContentHandler::StartApplication(), unchanged if the return value is false.
+  // |content_handler_url| is the url of the content handler application to
+  // run, unchanged if the return value is false.
+  // |qualifier| is the Identity qualifier that the content handler application
+  // instance should be associated with, unchanged if the return value is false.
+  virtual bool HandleWithContentHandler(Fetcher* fetcher,
+                                        const GURL& unresolved_url,
+                                        base::TaskRunner* task_runner,
+                                        URLResponsePtr* new_response,
+                                        GURL* content_handler_url,
+                                        std::string* qualifier) = 0;
+};
+
+}  // namespace shell
+}  // namespace mojo
+
+#endif  // MOJO_SHELL_PACKAGE_MANAGER_H_