Move BroadcastChannel browser code from components/ to content/browser.

components/webmessaging/broadcast_channel_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 COMPONENTS_WEBMESSAGING_BROADCAST_CHANNEL_PROVIDER_H_
-#define COMPONENTS_WEBMESSAGING_BROADCAST_CHANNEL_PROVIDER_H_
-
-#include <map>
-
-#include "base/memory/ref_counted.h"
-#include "components/webmessaging/public/interfaces/broadcast_channel.mojom.h"
-#include "mojo/public/cpp/bindings/binding_set.h"
-#include "url/origin.h"
-
-namespace webmessaging {
-
-class BroadcastChannelProvider
-    : public base::RefCountedThreadSafe<BroadcastChannelProvider>,
-      public mojom::BroadcastChannelProvider {
- public:
-  BroadcastChannelProvider();
-  void Connect(mojo::InterfaceRequest<mojom::BroadcastChannelProvider> request);
-
-  void ConnectToChannel(
-      const url::Origin& origin,
-      const mojo::String& name,
-      mojom::BroadcastChannelClientAssociatedPtrInfo client,
-      mojom::BroadcastChannelClientAssociatedRequest connection) override;
-
- private:
-  friend class base::RefCountedThreadSafe<BroadcastChannelProvider>;
-  class Connection;
-
-  ~BroadcastChannelProvider() override;
-
-  void UnregisterConnection(Connection*);
-  void ReceivedMessageOnConnection(Connection*, const mojo::String& message);
-
-  mojo::BindingSet<mojom::BroadcastChannelProvider> bindings_;
-  std::map<url::Origin, std::multimap<std::string, std::unique_ptr<Connection>>>
-      connections_;
-};
-
-}  // namespace webmessaging
-
-#endif  // COMPONENTS_WEBMESSAGING_BROADCAST_CHANNEL_PROVIDER_H_