Move content's shell connections to the IO thread

content/public/common/mojo_shell_connection.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 CONTENT_PUBLIC_COMMON_MOJO_SHELL_CONNECTION_H_
 #define CONTENT_PUBLIC_COMMON_MOJO_SHELL_CONNECTION_H_
 
 #include <memory>
 
 #include "base/callback_forward.h"
+#include "base/sequenced_task_runner.h"
 #include "content/common/content_export.h"
 #include "content/public/common/mojo_application_info.h"
 #include "services/shell/public/cpp/identity.h"
 #include "services/shell/public/interfaces/shell_client.mojom.h"
 
 namespace shell {
 class Connection;
 class Connector;
 class ShellConnection;
 }
 
 namespace content {
 
 // Encapsulates a connection to a //services/shell.
 // Access a global instance on the thread the ShellConnection was bound by
 // calling Holder::Get().
 // Clients can add shell::ShellClient implementations whose exposed interfaces
 // will be exposed to inbound connections to this object's ShellClient.
 // Alternatively clients can define named services that will be constructed when
 // requests for those service names are received.
 // Clients must call any of the registration methods when receiving
 // ContentBrowserClient::RegisterInProcessMojoApplications().
 class CONTENT_EXPORT MojoShellConnection {
  public:
   using ShellClientRequestHandler =
       base::Callback<void(shell::mojom::ShellClientRequest)>;
   using Factory = base::Callback<std::unique_ptr<MojoShellConnection>(void)>;
+  using ConnectionFilter =
+      base::Callback<bool(shell::Connection*, shell::Connector*)>;
 
   // Stores an instance of |connection| in TLS for the current process. Must be
   // called on the thread the connection was created on.
   static void SetForProcess(std::unique_ptr<MojoShellConnection> connection);
 
   // Returns the per-process instance, or nullptr if the Shell connection has
   // not yet been bound. Must be called on the thread the connection was created
   // on.
   static MojoShellConnection* GetForProcess();
 
   // Destroys the per-process instance. Must be called on the thread the
   // connection was created on.
   static void DestroyForProcess();
 
   virtual ~MojoShellConnection();
 
   // Sets the factory used to create the MojoShellConnection. This must be
   // called before the MojoShellConnection has been created.
   static void SetFactoryForTest(Factory* factory);
 
-  // Creates a MojoShellConnection from |request|.
+  // Creates a MojoShellConnection from |request|. The connection bind
+  // its interfaces and accept new connections on |io_task_runner| only.
   static std::unique_ptr<MojoShellConnection> Create(
-      shell::mojom::ShellClientRequest request);
+      shell::mojom::ShellClientRequest request,
+      scoped_refptr<base::SequencedTaskRunner> io_task_runner);
 
-  // Returns the bound shell::ShellConnection object.
-  // TODO(rockot): remove.
-  virtual shell::ShellConnection* GetShellConnection() = 0;
+  // Sets a closure to be invoked once the connection receives an Initialize()
+  // request from the shell.
+  virtual void SetInitializeHandler(const base::Closure& handler) = 0;
 
   // Returns the shell::Connector received via this connection's ShellClient
   // implementation. Use this to initiate connections as this object's Identity.
   virtual shell::Connector* GetConnector() = 0;
 
   // Returns this connection's identity with the shell. Connections initiated
   // via the shell::Connector returned by GetConnector() will use this.
   virtual const shell::Identity& GetIdentity() const = 0;
 
   // Sets a closure that is called when the connection is lost. Note that
   // connection may already have been closed, in which case |closure| will be
   // run immediately before returning from this function.
   virtual void SetConnectionLostClosure(const base::Closure& closure) = 0;
 
-  // Allows the caller to expose interfaces to the caller using the identity of
-  // this object's ShellClient. As distinct from AddEmbeddedService() and
-  // AddShellClientRequestHandler() which specify unique identities for the
-  // registered services.
-  virtual void AddEmbeddedShellClient(
-      std::unique_ptr<shell::ShellClient> shell_client) = 0;
-  virtual void AddEmbeddedShellClient(shell::ShellClient* shell_client) = 0;
+  // Allows the caller to filter inbound connections and/or expose interfaces
+  // on them. Note that ConnectionFilters are always invoked on the
+  // |io_task_runner| (see Create above.)
+  virtual void AddConnectionFilter(const ConnectionFilter& filter) = 0;
 
   // Adds an embedded service to this connection's ShellClientFactory.
   // |info| provides details on how to construct new instances of the
   // service when an incoming connection is made to |name|.
   virtual void AddEmbeddedService(const std::string& name,
                                   const MojoApplicationInfo& info) = 0;
 
   // Adds a generic ShellClientRequestHandler for a given service name. This
   // will be used to satisfy any incoming calls to CreateShellClient() which
   // reference the given name.
   //
   // For in-process services, it is preferable to use |AddEmbeddedService()| as
   // defined above.
   virtual void AddShellClientRequestHandler(
       const std::string& name,
       const ShellClientRequestHandler& handler) = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_MOJO_SHELL_CONNECTION_H_