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

remoting/host/single_window_input_injector_mac.cc

Index: remoting/host/single_window_input_injector_mac.cc
diff --git a/remoting/host/single_window_input_injector_mac.cc b/remoting/host/single_window_input_injector_mac.cc
index 3fac4ffac0c7c54ea03c2edaa6eaf4e78c89f772..333f684058d130e041d4304a227006562c893b71 100644
--- a/remoting/host/single_window_input_injector_mac.cc
+++ b/remoting/host/single_window_input_injector_mac.cc
@@ -18,6 +18,7 @@ using protocol::ClipboardEvent;
 using protocol::KeyEvent;
 using protocol::TextEvent;
 using protocol::MouseEvent;
+using protocol::TouchEvent;
 
 class SingleWindowInputInjectorMac : public SingleWindowInputInjector {
  public:
@@ -31,6 +32,7 @@ class SingleWindowInputInjectorMac : public SingleWindowInputInjector {
   void InjectKeyEvent(const KeyEvent& event) override;
   void InjectTextEvent(const TextEvent& event) override;
   void InjectMouseEvent(const MouseEvent& event) override;
+  void InjectTouchEvent(const TouchEvent& event) override;
   void InjectClipboardEvent(const ClipboardEvent& event) override;
 
  private:
@@ -107,6 +109,10 @@ void SingleWindowInputInjectorMac::InjectMouseEvent(const MouseEvent& event) {
   }
 }
 
+void SingleWindowInputInjectorMac::InjectTouchEvent(const TouchEvent& event) {
+  NOTIMPLEMENTED();
+}
+
 void SingleWindowInputInjectorMac::InjectClipboardEvent(
     const ClipboardEvent& event) {
   input_injector_->InjectClipboardEvent(event);