Add extensions code to use common updater in components/update_client/

extensions/browser/updater/update_client_config.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 EXTENSIONS_BROWSER_UPDATER_UPDATE_CLIENT_CONFIG_H_
+#define EXTENSIONS_BROWSER_UPDATER_UPDATE_CLIENT_CONFIG_H_
+
+#include <string>
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "components/update_client/configurator.h"
+
+class GURL;
+
+namespace base {
+class SequencedTaskRunner;
+class SingleThreadTaskRunner;
+}
+
+namespace content {
+class BrowserContext;
+}
+
+namespace update_client {
+class OutOfProcessPatcher;
+}
+
+namespace extensions {
+
+// Used to provide configuration settings to the UpdateClient.
+class UpdateClientConfig : public update_client::Configurator {

[Sorin Jianu, 2015/10/02 00:05:10]

The configurators are a sore point of our design (don't know how to make this
better though).
Would you like to take a look and see if you can reuse configurator_impl.cc th
way IOSConfigurator does?

[asargent_no_longer_on_chrome, 2015/10/06 21:31:17]

Oh, I've been meaning to touch base with you guys about this - I decided not to
use configurator_impl.cc because of the CanUseAltUrlSource() method that lets us
fallback to http. In conversations I had with the security team they wanted to
make sure that it was never possible to fallback to downloading the differential
update patches over http, and only ever use https. 

The right solution might be to get rid of the fallback entirely for all use
cases.

[Sorin Jianu, 2015/10/08 22:57:54]

I think we can extend the design so this aspect is customizable by the client
reusing this code.
Right now the behavior is runtime-dependent on
base::win::MaybeHasSHA256Support(); but we can allow an override so other
implementations will always return 'false' if the fallback is not needed.

[asargent_no_longer_on_chrome, 2015/10/14 17:04:31]

Ok, I've added a set_require_secure_transport() method to ConfiguratorImpl, and
am using it on the ConfiguratorImpl instance that I now am using in
ChromeUpdateClientConfig

[Sorin Jianu, 2015/10/14 20:37:09]

Acknowledged.

+ public:
+  explicit UpdateClientConfig(content::BrowserContext* context);
+
+  int InitialDelay() const override;
+  int NextCheckDelay() const override;
+  int StepDelay() const override;
+  int OnDemandDelay() const override;
+  int UpdateDelay() const override;
+  std::string GetOSLongName() const override;
+  std::string ExtraRequestParams() const override;
+
+  net::URLRequestContextGetter* RequestContext() const override;
+
+  scoped_refptr<update_client::OutOfProcessPatcher> CreateOutOfProcessPatcher()
+      const override;
+
+  bool DeltasEnabled() const override;
+
+  bool UseBackgroundDownloader() const override;
+
+  scoped_refptr<base::SequencedTaskRunner> GetSequencedTaskRunner()
+      const override;
+
+  scoped_refptr<base::SingleThreadTaskRunner> GetSingleThreadTaskRunner()
+      const override;
+
+ protected:
+  friend class base::RefCountedThreadSafe<UpdateClientConfig>;
+  ~UpdateClientConfig() override;
+
+ private:
+  content::BrowserContext* context_;
+
+  DISALLOW_COPY_AND_ASSIGN(UpdateClientConfig);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_UPDATER_UPDATE_CLIENT_CONFIG_H_