X11: Remove calls to XSelectInput

ui/aura/window_tree_host_x11.cc

Index: ui/aura/window_tree_host_x11.cc
diff --git a/ui/aura/window_tree_host_x11.cc b/ui/aura/window_tree_host_x11.cc
index 0bbd0a0ce0e799f47c777b9438f6d89e5cb8fea0..37efdf4b65b98773ed5e6c2d276d375c6a7f76bc 100644
--- a/ui/aura/window_tree_host_x11.cc
+++ b/ui/aura/window_tree_host_x11.cc
@@ -34,6 +34,7 @@
 #include "ui/base/ui_base_switches.h"
 #include "ui/base/view_prop.h"
 #include "ui/base/x/x11_util.h"
+#include "ui/base/x/x11_window_event_manager.h"
 #include "ui/compositor/compositor.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/compositor/layer.h"
@@ -63,6 +64,14 @@ const char* kAtomsToCache[] = {
   NULL
 };
 
+constexpr uint32_t kInputEventMask =
+    ButtonPressMask | ButtonReleaseMask | FocusChangeMask | KeyPressMask |
+    KeyReleaseMask | EnterWindowMask | LeaveWindowMask | PointerMotionMask;
+
+constexpr uint32_t kEventMask = kInputEventMask | ExposureMask |
+                                VisibilityChangeMask | StructureNotifyMask |
+                                PropertyChangeMask;
+
 ::Window FindEventTarget(const base::NativeEvent& xev) {
   ::Window target = xev->xany.window;
   if (xev->type == GenericEvent)
@@ -132,13 +141,7 @@ WindowTreeHostX11::WindowTreeHostX11(const gfx::Rect& bounds)
   if (ui::PlatformEventSource::GetInstance())
     ui::PlatformEventSource::GetInstance()->AddPlatformEventDispatcher(this);
 
-  long event_mask = ButtonPressMask | ButtonReleaseMask | FocusChangeMask |
-                    KeyPressMask | KeyReleaseMask |
-                    EnterWindowMask | LeaveWindowMask |
-                    ExposureMask | VisibilityChangeMask |
-                    StructureNotifyMask | PropertyChangeMask |
-                    PointerMotionMask;
-  XSelectInput(xdisplay_, xwindow_, event_mask);
+  xwindow_events_.reset(new ui::XScopedEventSelector(xwindow_, kEventMask));
   XFlush(xdisplay_);
 
   if (ui::IsXInput2Available()) {
@@ -470,6 +473,17 @@ void WindowTreeHostX11::MoveCursorToNative(const gfx::Point& location) {
 void WindowTreeHostX11::OnCursorVisibilityChangedNative(bool show) {
 }
 
+void WindowTreeHostX11::DisableInput() {
+  xwindow_events_.reset(

[Daniel Erat, 2016/09/07 23:36:16]

is there a risk that we can miss some events between the point where the old
selector is destroyed and the new one is created? if so, it might be safer to
put the new selector in a local unique_ptr first and use .swap().

[Tom (Use chromium acct), 2016/09/08 17:15:15]

The new XScopedEventSelector gets created before the old one is destroyed by the
reset(), so I don't think there's any possibility of losing events here.

[Daniel Erat, 2016/09/08 18:11:28]

oh, duh. yes. :-)

+      new ui::XScopedEventSelector(xwindow_, kEventMask & ~kInputEventMask));
+  unsigned char mask[XIMaskLen(XI_LASTEVENT)] = {0};
+  XIEventMask evmask;
+  evmask.deviceid = XIAllDevices;
+  evmask.mask_len = sizeof(mask);
+  evmask.mask = mask;
+  XISelectEvents(gfx::GetXDisplay(), xwindow_, &evmask, 1);
+}
+
 void WindowTreeHostX11::DispatchXI2Event(const base::NativeEvent& event) {
   ui::TouchFactory* factory = ui::TouchFactory::GetInstance();
   XEvent* xev = event;