Host extensions

This CL introduces HostExtension, an interface for classes that
extend the host with non-core functionality.

Extensions are added to the ChromotingHost. They are used to compile
the list of capabilities reported to the client, which can be used by
the client to determine the availability of the extension.

When a client connects, a HostExtension has the opportunity to create
an HostExtensionSession to hold client/extension state, and to handle
extension messages from that client.

BUG=

NOTRY=true

Review URL: https://codereview.chromium.org/301453003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@273901 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 22 insertions, 0 deletions

diff --git a/remoting/host/client_session.h b/remoting/host/client_session.h
index f892329..a86839e 100644
--- a/remoting/host/client_session.h
+++ b/remoting/host/client_session.h
@@ -8,6 +8,7 @@
 #include <string>
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "base/sequenced_task_runner_helpers.h"
 #include "base/threading/non_thread_safe.h"
@@ -15,6 +16,8 @@
 #include "base/timer/timer.h"
 #include "remoting/host/client_session_control.h"
 #include "remoting/host/gnubby_auth_handler.h"
+#include "remoting/host/host_extension.h"
+#include "remoting/host/host_extension_session.h"
 #include "remoting/host/mouse_clamping_filter.h"
 #include "remoting/host/remote_input_filter.h"
 #include "remoting/protocol/clipboard_echo_filter.h"
@@ -64,6 +67,9 @@ class ClientSession
     // Called after we've finished connecting all channels.
     virtual void OnSessionChannelsConnected(ClientSession* client) = 0;
 
+    // Called after client has reported capabilities.
+    virtual void OnSessionClientCapabilities(ClientSession* client) = 0;
+
     // Called after authentication has failed. Must not tear down this
     // object. OnSessionClosed() is notified after this handler
     // returns.
@@ -103,6 +109,13 @@ class ClientSession
       scoped_refptr<protocol::PairingRegistry> pairing_registry);
   virtual ~ClientSession();
 
+  // Adds an extension to client to handle extension messages.
+  void AddExtensionSession(scoped_ptr<HostExtensionSession> extension_session);
+
+  // Adds extended capabilities to advertise to the client, e.g. those
+  // implemented by |DesktopEnvironment| or |HostExtension|s.
+  void AddHostCapabilities(const std::string& capability);
+
   // protocol::HostStub interface.
   virtual void NotifyClientResolution(
       const protocol::ClientResolution& resolution) OVERRIDE;
@@ -148,7 +161,13 @@ class ClientSession
 
   bool is_authenticated() { return auth_input_filter_.enabled();  }
 
+  const std::string* client_capabilities() const {
+    return client_capabilities_.get();
+  }
+
  private:
+  typedef ScopedVector<HostExtensionSession> HostExtensionSessionList;
+
   // Creates a proxy for sending clipboard events to the client.
   scoped_ptr<protocol::ClipboardStub> CreateClipboardProxy();
 
@@ -244,6 +263,9 @@ class ClientSession
   // Used to proxy gnubby auth traffic.
   scoped_ptr<GnubbyAuthHandler> gnubby_auth_handler_;
 
+  // Host extension sessions, used to handle extension messages.
+  HostExtensionSessionList extension_sessions_;
+
   DISALLOW_COPY_AND_ASSIGN(ClientSession);
 };