Make PointerDeviceObserver work under Ozone

chrome/browser/chromeos/system/pointer_device_observer.cc

 // Copyright (c) 2012 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 "chrome/browser/chromeos/system/pointer_device_observer.h"
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "chrome/browser/chromeos/system/input_device_settings.h"
 #include "content/public/browser/browser_thread.h"
+#include "ui/events/devices/device_data_manager.h"
 
 #if defined(USE_X11)
 #include "chrome/browser/chromeos/events/xinput_hierarchy_changed_event_listener.h"
 #endif
 
 using content::BrowserThread;
 
 namespace chromeos {
 namespace system {
 
 PointerDeviceObserver::PointerDeviceObserver()
     : weak_factory_(this) {
 }
 
 PointerDeviceObserver::~PointerDeviceObserver() {
 #if defined(USE_X11)
   XInputHierarchyChangedEventListener::GetInstance()
       ->RemoveObserver(this);
+#elif defined(USE_OZONE)
+  ui::DeviceDataManager::GetInstance()->RemoveObserver(this);

[sadrul, 2015/02/03 15:29:04]

There's no reason to add this ifdef. We should just remove
XInputHierarchyChangedEventListener and DeviceHierarchyObserver, and use the
same pattern (i.e. use InputDeviceEventObserver) on X11. (you can reference
issue 360377)

[pkotwicz, 2015/02/03 16:50:14]

I completely agree. I am not doing this as part of this CL because the bug is
marked as M41 release-block stable. I think that it will be easier to convince
dharani@ that the CL can be merged back if I do not modify the X11 code path. I
can file a bug and reference the bug in the code.

If we merge back this CL, we will need to merge back at least some of
https://codereview.chromium.org/868043003

dharani@ seems keen to have this bug fixed in M41. Do you have any suggestions
as to how to make this CL simpler?

Should I investigate in what the consequences would be if the all of the users
of PointerDeviceObserver thought that the mouse and touchpad always existed on
Ozone in M41?

[sadrul, 2015/02/03 17:33:04]

Unfortunately no. Providing default no-op impls on the new observer methods
(which I think we should always do; it doesn't make sense to force observers to
override everything) would make the line count smaller. But I don't know how
much that would help in terms of making this simple.
I am unsure. You can get confirmation from dharani@

 #endif
 }
 
 void PointerDeviceObserver::Init() {
 #if defined(USE_X11)
   XInputHierarchyChangedEventListener::GetInstance()
       ->AddObserver(this);
+#elif defined(USE_OZONE)
+  ui::DeviceDataManager::GetInstance()->AddObserver(this);
 #endif
 }
 
 void PointerDeviceObserver::CheckDevices() {
   CheckMouseExists();
   CheckTouchpadExists();
 }
 
 void PointerDeviceObserver::AddObserver(Observer* observer) {
   observers_.AddObserver(observer);
 }
 
 void PointerDeviceObserver::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
 void PointerDeviceObserver::DeviceHierarchyChanged() {
   CheckDevices();
 }
 
+void PointerDeviceObserver::OnMouseDeviceConfigurationChanged() {
+  CheckDevices();
+}
+
+void PointerDeviceObserver::OnTouchpadDeviceConfigurationChanged() {
+  CheckDevices();
+}
+
 void PointerDeviceObserver::CheckTouchpadExists() {
   InputDeviceSettings::Get()->TouchpadExists(
       base::Bind(&PointerDeviceObserver::OnTouchpadExists,
                  weak_factory_.GetWeakPtr()));

[sadrul, 2015/02/03 17:33:04]

side rant: eh, why is there an ozone implementation of InputDeviceSettings? Why
didn't we go through DDM?

 }
 
 void PointerDeviceObserver::CheckMouseExists() {
   InputDeviceSettings::Get()->MouseExists(
       base::Bind(&PointerDeviceObserver::OnMouseExists,
                  weak_factory_.GetWeakPtr()));
 }
 
 void PointerDeviceObserver::OnTouchpadExists(bool exists) {
   FOR_EACH_OBSERVER(Observer, observers_, TouchpadExists(exists));
 }
 
 void PointerDeviceObserver::OnMouseExists(bool exists) {
   FOR_EACH_OBSERVER(Observer, observers_, MouseExists(exists));
 }
 
 PointerDeviceObserver::Observer::~Observer() {
 }
 
 }  // namespace system
 }  // namespace chromeos