chromeos: converts observed pointer events to DIPs

services/ui/ws/window_tree.cc

Index: services/ui/ws/window_tree.cc
diff --git a/services/ui/ws/window_tree.cc b/services/ui/ws/window_tree.cc
index 53224669f80d28dedf688fec7b56e0b581f1be56..ce6c4a6ea32c1c4c890e4aca53bc3315951d4468 100644
--- a/services/ui/ws/window_tree.cc
+++ b/services/ui/ws/window_tree.cc
@@ -798,7 +798,8 @@ void WindowTree::ProcessWindowSurfaceChanged(
 }
 
 void WindowTree::SendToPointerWatcher(const ui::Event& event,
-                                      ServerWindow* target_window) {
+                                      ServerWindow* target_window,
+                                      int64_t display_id) {
   if (!EventMatchesPointerWatcher(event))
     return;
 
@@ -806,8 +807,8 @@ void WindowTree::SendToPointerWatcher(const ui::Event& event,
   // Ignore the return value from IsWindowKnown() as in the case of the client
   // not knowing the window we'll send 0, which corresponds to no window.
   IsWindowKnown(target_window, &client_window_id);
-  client()->OnPointerEventObserved(ui::Event::Clone(event),
-                                   client_window_id.id);
+  client()->OnPointerEventObserved(ui::Event::Clone(event), client_window_id.id,
+                                   display_id);
 }
 
 bool WindowTree::ShouldRouteToWindowManager(const ServerWindow* window) const {
@@ -1146,8 +1147,10 @@ void WindowTree::DispatchInputEventImpl(ServerWindow* target,
   // Should only get events from windows attached to a host.
   DCHECK(event_source_wms_);
   bool matched_pointer_watcher = EventMatchesPointerWatcher(event);
+  Display* display = GetDisplay(target);
+  DCHECK(display);

[riajiang, 2017/02/09 00:33:26]

I thought there are checks in WindowTreeClient::OnWindowInputEvent to see if the
window it received from WindowTree is null? If the |target| here can be null,
then this |display| can be null? If the window cannot be null, would the
device_scale_factor we get that's associated with this display the same as if we
use the target window in WindowTreeClient::ScaleFactorForDisplay?

[sky, 2017/02/09 00:35:36]

In this function the window should never be null.
WindowTreeClient::OnWindowInputEvent() is asynchronously called though, so it's
entirely possible for the client to see a null window by the time it gets the
event.

[riajiang, 2017/02/09 02:53:42]

Oh I see, thanks for your clarification!

   client()->OnWindowInputEvent(
-      event_ack_id_, ClientWindowIdForWindow(target).id,
+      event_ack_id_, ClientWindowIdForWindow(target).id, display->GetId(),
       ui::Event::Clone(event), matched_pointer_watcher);
 }