mus: Add PointerWatcher for passively observing mouse and touch events

content/renderer/mus/compositor_mus_connection.cc

 // Copyright 2015 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.
 
 #include "content/renderer/mus/compositor_mus_connection.h"
 
 #include "base/single_thread_task_runner.h"
 #include "content/common/input/web_input_event_traits.h"
 #include "content/renderer/input/input_handler_manager.h"
 #include "content/renderer/mus/render_widget_mus_connection.h"
@@ skipping 98 matching lines @@
 void CompositorMusConnection::OnEmbed(mus::Window* root) {
   DCHECK(compositor_task_runner_->BelongsToCurrentThread());
   root_ = root;
   root_->set_input_event_handler(this);
   if (window_surface_binding_) {
     root->AttachSurface(mus::mojom::SurfaceType::DEFAULT,
                         std::move(window_surface_binding_));
   }
 }
 
+void CompositorMusConnection::OnEventObserved(const ui::Event& event) {
+  // Compositor does not use SetEventObserver().
+}
+
 void CompositorMusConnection::OnWindowInputEvent(
     mus::Window* window,
     const ui::Event& event,
     std::unique_ptr<base::Callback<void(EventResult)>>* ack_callback) {
   DCHECK(compositor_task_runner_->BelongsToCurrentThread());
   // TODO(moshayedi): Convert ui::Event directly to blink::WebInputEvent.
   std::unique_ptr<blink::WebInputEvent> web_event(
       mus::mojom::Event::From(event)
           .To<std::unique_ptr<blink::WebInputEvent>>());
   // TODO(sad): We probably need to plumb LatencyInfo through Mus.
@@ skipping 17 matching lines @@
                    this, *ack_callback->get());
     ack_callback->reset();
   }
   main_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&CompositorMusConnection::OnWindowInputEventOnMainThread, this,
                  base::Passed(std::move(web_event)), ack));
 }
 
 }  // namespace content