Add touch events to the protocol, the stub layer, and to the client plugin.

remoting/host/remote_input_filter.h

Index: remoting/host/remote_input_filter.h
diff --git a/remoting/host/remote_input_filter.h b/remoting/host/remote_input_filter.h
index 1d2301cca12410c897da5240d457d5b0c25017ae..8645db1930ede600c24256b0a22969b223747b2f 100644
--- a/remoting/host/remote_input_filter.h
+++ b/remoting/host/remote_input_filter.h
@@ -36,6 +36,7 @@ class RemoteInputFilter : public protocol::InputStub {
   void InjectKeyEvent(const protocol::KeyEvent& event) override;
   void InjectTextEvent(const protocol::TextEvent& event) override;
   void InjectMouseEvent(const protocol::MouseEvent& event) override;
+  void InjectTouchEvent(const protocol::TouchEvent& event) override;
 
  private:
   bool ShouldIgnoreInput() const;