Add the supporting code for the cast system tray integration

ash/cast_config_delegate.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 ASH_CAST_CONFIG_DELEGATE_H_
+#define ASH_CAST_CONFIG_DELEGATE_H_
+
+#include <map>
+#include <string>
+
+#include "ash/ash_export.h"
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/string16.h"
+#include "url/gurl.h"
+
+namespace ash {
+
+// This delegate allows the UI code in ash, e.g. |TrayCastDetailedView|,
+// to access the cast extension.
+class CastConfigDelegate {
+ public:
+  struct ASH_EXPORT Receiver {
+    Receiver();
+    ~Receiver();
+
+    std::string id;
+    base::string16 name;
+  };
+
+  struct ASH_EXPORT Activity {
+    // The tab identifier that we are casting. These are the special tab values
+    // taken from the chromecast extension itself. If an actual tab is being
+    // casted, then the TabId will be >= 0.
+    enum TabId {
+      EXTENSION = -1,
+      DESKTOP = -2,
+      DISCOVERED_ACTIVITY = -3,
+      EXTERNAL_EXTENSION_CLIENT = -4
+    };
+
+    Activity();
+    ~Activity();
+
+    std::string id;
+    base::string16 title;
+    std::string activity_type;
+    bool allow_stop = false;
+
+    // The id for the tab we are casting. Could be one of the TabId values,
+    // or a value >= 0 that represents that tab index of the tab we are
+    // casting. We default to casting the desktop, as a tab may not
+    // necessarily exist.
+    int tab_id = TabId::DESKTOP;
+  };
+
+  struct ASH_EXPORT ReceiverAndActivity {
+    ReceiverAndActivity();
+    ~ReceiverAndActivity();
+
+    Receiver receiver;
+    Activity activity;
+  };
+
+  // The key is the receiver id.
+  using ReceiversAndActivites = std::map<std::string, ReceiverAndActivity>;
+  using ReceiversAndActivitesCallback =
+      base::Callback<void(const ReceiversAndActivites&)>;
+
+  virtual ~CastConfigDelegate() {}
+
+  // Returns true if cast extension is installed.
+  virtual bool HasCastExtension() const = 0;
+
+  // Fetches the current set of receivers and their possible activities. This
+  // method will lookup the current chromecast extension and query its current
+  // state. The |callback| will be invoked when the receiver/activity data is
+  // available.
+  virtual void GetReceiversAndActivities(
+      const ReceiversAndActivitesCallback& callback) = 0;
+
+  // Cast to a receiver specified by |receiver_id|.
+  virtual void CastToReceiver(const std::string& receiver_id) = 0;
+
+  // Stop ongoing cast. The |activity_id| is the unique identifier associated
+  // with the ongoing cast. Each receiver has only one possible activity
+  // associated with it. The |activity_id| is available by invoking
+  // GetReceiversAndActivities(); if the receiver is currently casting, then the
+  // associated activity data will have an id. This id can be used to stop the
+  // cast in this method.
+  virtual void StopCasting(const std::string& activity_id) = 0;
+
+  // Opens Options page for cast.
+  virtual void LaunchCastOptions() = 0;
+
+ private:
+  DISALLOW_ASSIGN(CastConfigDelegate);
+};
+
+}  // namespace ash
+
+#endif  // ASH_CAST_CONFIG_DELEGATE_H_