X11: Remove calls to XSelectInput

ui/base/x/x11_window_event_manager.cc

-// Copyright 2014 The Chromium Authors. All rights reserved.
+// Copyright 2016 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 "ui/base/x/x11_window_event_manager.h"
 
 #include <stddef.h>
 #include <X11/Xlib.h>
 #include <X11/Xlib-xcb.h>
 #include <xcb/xcb.h>
 
-#include "base/compiler_specific.h"
 #include "base/memory/singleton.h"
 
 namespace ui {
 
 XScopedEventSelector::XScopedEventSelector(XID xid, uint32_t event_mask)
-    : xid_(xid), event_mask_(event_mask) {
-  XWindowEventManager::GetInstance()->SelectEvents(xid_, event_mask_);
+    : xid_(xid),
+      event_mask_(event_mask),
+      event_manager_(
+          XWindowEventManager::GetInstance()->weak_ptr_factory_.GetWeakPtr()) {
+  event_manager_->SelectEvents(xid_, event_mask_);
 }
 
 XScopedEventSelector::~XScopedEventSelector() {
-  XWindowEventManager::GetInstance()->DeselectEvents(xid_, event_mask_);
+  if (event_manager_)
+    event_manager_->DeselectEvents(xid_, event_mask_);
 }
 
 // static
 XWindowEventManager* XWindowEventManager::GetInstance() {
   return base::Singleton<XWindowEventManager>::get();
 }
 
 class XWindowEventManager::MultiMask {
  public:
   MultiMask() {
@@ skipping 29 matching lines @@
   }
 
  private:
   static constexpr auto kMaskSize = 25;
 
   int mask_bits_[kMaskSize];
 
   DISALLOW_COPY_AND_ASSIGN(MultiMask);
 };
 
-XWindowEventManager::XWindowEventManager() {}
-XWindowEventManager::~XWindowEventManager() {}
+XWindowEventManager::XWindowEventManager() : weak_ptr_factory_(this) {}
+
+XWindowEventManager::~XWindowEventManager() {
+  for (const auto& mask_pair : mask_map_)

[Daniel Erat, 2016/09/14 04:56:09]

i'd recommend adding a comment here like:

  // Clear events still requested by not-yet-deleted XScopedEventSelectors.

[Tom (Use chromium acct), 2016/09/14 17:51:08]

Done.

+    ChangeEventMask(mask_pair.first, NoEventMask);
+}
 
 void XWindowEventManager::SelectEvents(XID xid, uint32_t event_mask) {
   std::unique_ptr<MultiMask>& mask = mask_map_[xid];
   if (!mask)
     mask.reset(new MultiMask());
   uint32_t old_mask = mask_map_[xid]->ToMask();
   mask->AddMask(event_mask);
   AfterMaskChanged(xid, old_mask);
 }
 
 void XWindowEventManager::DeselectEvents(XID xid, uint32_t event_mask) {
   DCHECK(mask_map_.find(xid) != mask_map_.end());
   std::unique_ptr<MultiMask>& mask = mask_map_[xid];
   uint32_t old_mask = mask->ToMask();
   mask->RemoveMask(event_mask);
   AfterMaskChanged(xid, old_mask);
 }
 
 void XWindowEventManager::AfterMaskChanged(XID xid, uint32_t old_mask) {
   uint32_t new_mask = mask_map_[xid]->ToMask();
   if (new_mask == old_mask)
     return;
 
+  ChangeEventMask(xid, new_mask);
+
+  if (new_mask == NoEventMask)
+    mask_map_.erase(xid);
+}
+
+void XWindowEventManager::ChangeEventMask(XID xid, uint32_t new_mask) {
   XDisplay* display = gfx::GetXDisplay();
   xcb_connection_t* connection = XGetXCBConnection(display);
   auto cookie = xcb_change_window_attributes(connection, xid, XCB_CW_EVENT_MASK,
                                              &new_mask);
   // Window |xid| may already be destroyed at this point, so the
   // change_attributes request may give a BadWindow error.  In this case, just
   // ignore the error.
   xcb_discard_reply(connection, cookie.sequence);
-
-  if (new_mask == NoEventMask)
-    mask_map_.erase(xid);
 }
 
 }  // namespace ui