Added AddDownload communication path and observers

content/browser/background_fetch/background_fetch_client_proxy.h

 // 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 CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_CLIENT_PROXY_H_
 #define CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_CLIENT_PROXY_H_
 
 #include <string>
 
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "content/public/browser/background_fetch_client.h"
 
 namespace content {
 
 class BackgroundFetchContext;
+class BrowserContext;
+struct BackgroundFetchOptions;
 
 // The BackgroundFetchClientProxy exists to proxy calls from the
 // BackgroundFetchContext, which lives on the IO thread, to the
 // BackgroundFetchClient which lives on the UI thread and back through the
 // BackgroundFetchClient::Delegate.
 class CONTENT_EXPORT BackgroundFetchClientProxy
     : public BackgroundFetchClient::Delegate {
  public:
-  explicit BackgroundFetchClientProxy(BackgroundFetchContext* context);
+  explicit BackgroundFetchClientProxy(
+      BrowserContext* browser_context,

[harkness, 2017/04/20 12:25:16]

peter@ : I didn't really want to save the browser_context in the proxy, but I
don't see a way around it. I'm open to alternative suggestions.

+      BackgroundFetchContext* background_fetch_context);
   ~BackgroundFetchClientProxy() override;
 
+  // Returns a weak pointer that can be used to post tasks to the proxy.
+  base::WeakPtr<BackgroundFetchClientProxy> GetWeakPtr();
+
+  // Notify the BackgroundFetchClient that a new download item is available.
+  void AddDownload(const std::string& registration_id,
+                   const BackgroundFetchOptions& options);
+
   // BackgroundFetchClient::Delegate implementation.
   void CleanupAllTasks() override;
   void CancelDownload(const std::string& registration_id) override;
   void PauseDownload(const std::string& registration_id) override;
   void ResumeDownload(const std::string& registration_id) override;
 
  private:
+  // The BackgroundFetchClientProxy is indirectly owned by the BrowserContext.
+  BrowserContext* browser_context_;
+
   // The BackgroundFetchClientProxy is owned by the BackgroundFetchContext.
   BackgroundFetchContext* background_fetch_context_;
 
+  base::WeakPtrFactory<BackgroundFetchClientProxy> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(BackgroundFetchClientProxy);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_CLIENT_PROXY_H_