[ios] Adds OmahaServiceProvider.

ios/public/provider/chrome/browser/omaha/omaha_service_provider.h

+// Copyright 2016 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 IOS_PUBLIC_PROVIDER_CHROME_BROWSER_OMAHA_OMAHA_SERVICE_PROVIDER_H_
+#define IOS_PUBLIC_PROVIDER_CHROME_BROWSER_OMAHA_OMAHA_SERVICE_PROVIDER_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "url/gurl.h"
+
+class OmahaXmlWriter;
+
+// OmahaServiceProvider provides the OmahaService with URLs and other data that
+// are necessary to send update requests.
+class OmahaServiceProvider {
+ public:
+  OmahaServiceProvider();
+  virtual ~OmahaServiceProvider();
+
+  // Returns the URL to use for update checks.
+  virtual GURL GetUpdateServerURL() const;
+
+  // Returns the unique ID for this application. The returned value may depend
+  // on bundle id, channel, or form factor.
+  virtual std::string GetApplicationID() const;
+
+  // Returns the default brand code for this installation.  The returned value
+  // may depend on bundle id, channel, or form factor.  Returns the empty string
+  // if this installation is not associated with a brand code.
+  virtual std::string GetBrandCode() const;
+
+  // Allows the embedder to append embedder-specific attributes to the XML
+  // request.  This method may be called multiple times per request.  Embedders
+  // should only add attributes that are relevant for the given element |tag|.
+  virtual void AppendExtraAttributes(const std::string& tag,
+                                     OmahaXmlWriter* writer) const;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(OmahaServiceProvider);
+};
+
+#endif  // IOS_PUBLIC_PROVIDER_CHROME_BROWSER_OMAHA_OMAHA_SERVICE_PROVIDER_H_