linux/x11: Fix event dispatch in menus in High DPI.

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
index 80008cf758a96e9faacbf9a81201934f23ea43b9..fd739cb6e535509feff28d19f76b14942bfbb36f 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc
@@ -1432,7 +1432,7 @@ void DesktopWindowTreeHostX11::DispatchMouseEvent(ui::MouseEvent* event) {
   } else {
     // Another DesktopWindowTreeHostX11 has installed itself as
     // capture. Translate the event's location and dispatch to the other.
-    event->ConvertLocationToTarget(window(), g_current_capture->window());
+    UpdateEventLocationForDifferentHost(event, g_current_capture);
     g_current_capture->SendEventToProcessor(event);
   }
 }
@@ -1440,13 +1440,29 @@ void DesktopWindowTreeHostX11::DispatchMouseEvent(ui::MouseEvent* event) {
 void DesktopWindowTreeHostX11::DispatchTouchEvent(ui::TouchEvent* event) {
   if (g_current_capture && g_current_capture != this &&
       event->type() == ui::ET_TOUCH_PRESSED) {
-    event->ConvertLocationToTarget(window(), g_current_capture->window());
+    UpdateEventLocationForDifferentHost(event, g_current_capture);
     g_current_capture->SendEventToProcessor(event);
   } else {
     SendEventToProcessor(event);
   }
 }
 
+void DesktopWindowTreeHostX11::UpdateEventLocationForDifferentHost(

[pkotwicz, 2015/02/13 20:15:35]

Nit: I think that ConvertEventToDifferentHost() is clearer.

[sadrul, 2015/02/13 20:27:36]

Done.

+    ui::LocatedEvent* located_event,
+    DesktopWindowTreeHostX11* host) {
+  DCHECK_NE(this, host);
+  const gfx::Display display_src =
+      gfx::Screen::GetNativeScreen()->GetDisplayNearestWindow(window());
+  const gfx::Display display_dest =
+      gfx::Screen::GetNativeScreen()->GetDisplayNearestWindow(host->window());
+  DCHECK_EQ(display_src.device_scale_factor(),
+            display_dest.device_scale_factor());
+  gfx::Vector2d offset = GetLocationOnNativeScreen() -
+                         g_current_capture->GetLocationOnNativeScreen();

[pkotwicz, 2015/02/13 20:15:35]

g_current_capture -> host

[sadrul, 2015/02/13 20:27:36]

whoops. Done.

+  gfx::Point location_in_pixel = located_event->location() + offset;

[pkotwicz, 2015/02/13 20:15:35]

Nit: This variable name is confusing. Is "pixel" the name of yet another
coordinate system? Maybe rename |host| to |other_host| and rename
|location_in_pixel| to |location_in_other_host|

[sadrul, 2015/02/13 20:27:36]

'pixel' here means 'physical pixels' (for device-independent pixels). We use
_in_pixel (and _in_dip) suffixes in a lot of ui code to mean these coord space.
I want to be explicit here too that the location here is in physical pixel
space.

Renamed to location_in_pixel_in_host (since |host| is the variable name).

[sadrul, 2015/02/13 20:31:09]

Should read: "'pixel' here means 'physical pixels' (*as opposed to*
device-independent pixels). ..."

+  located_event->set_location(location_in_pixel);
+}
+
 void DesktopWindowTreeHostX11::ResetWindowRegion() {
   // If a custom window shape was supplied then apply it.
   if (custom_window_shape_) {