Move ClientSession's input logic into separate components.

remoting/host/client_session.h

Index: remoting/host/client_session.h
diff --git a/remoting/host/client_session.h b/remoting/host/client_session.h
index 44607c47b1bed2f308a89d77d844ae0804f13862..12c74b3c4d5d6531181f1410b371448b6e9250e6 100644
--- a/remoting/host/client_session.h
+++ b/remoting/host/client_session.h
@@ -13,6 +13,7 @@
 #include "remoting/protocol/connection_to_client.h"
 #include "remoting/protocol/host_stub.h"
 #include "remoting/protocol/input_stub.h"
+#include "remoting/protocol/key_event_tracker.h"
 #include "third_party/skia/include/core/SkPoint.h"
 
 namespace remoting {
@@ -130,8 +131,8 @@ class ClientSession : public protocol::HostStub,
 
   std::string client_jid_;
 
-  // The input stub to which this object delegates.
-  protocol::InputStub* input_stub_;
+  // Key event tracker to allow us to release all pressed keys on disconnect.
+  protocol::KeyEventTracker key_tracker_;
 
   // Capturer, used to determine current screen size for ensuring injected
   // mouse events fall within the screen area.
@@ -160,10 +161,6 @@ class ClientSession : public protocol::HostStub,
 
   base::Time latest_local_input_time_;
 
-  // Set of keys that are currently pressed down by the user. This is used so
-  // we can release them if the user disconnects.
-  std::set<int> pressed_keys_;
-
   DISALLOW_COPY_AND_ASSIGN(ClientSession);
 };