Changed DeviceDataManager to be able to create multiple instances for the purposes of test.

The DeviceDataManager was implemented as a singleton and it was impossible
to create two different instances in tests. This change makes it possible
for future test framework to create multiple instances.

BUG=499476

Review URL: https://codereview.chromium.org/1202383002

Cr-Commit-Position: refs/heads/master@{#336558}

3 files changed, 25 insertions, 10 deletions

diff --git a/ui/events/devices/device_data_manager.cc b/ui/events/devices/device_data_manager.cc
index 44ca1fa..e725736 100644
--- a/ui/events/devices/device_data_manager.cc
+++ b/ui/events/devices/device_data_manager.cc
@@ -25,29 +25,35 @@ bool InputDeviceEquals(const ui::InputDevice& a, const ui::InputDevice& b) {
 DeviceDataManager* DeviceDataManager::instance_ = NULL;
 
 DeviceDataManager::DeviceDataManager() {
-  CHECK(!instance_) << "Can not create multiple instances of DeviceDataManager";
-  instance_ = this;
-
-  base::AtExitManager::RegisterTask(
-      base::Bind(&base::DeletePointer<DeviceDataManager>, this));
-
   ClearTouchDeviceAssociations();
 }
 
 DeviceDataManager::~DeviceDataManager() {
-  CHECK_EQ(this, instance_);
-  instance_ = NULL;
 }
 
 // static
 DeviceDataManager* DeviceDataManager::instance() { return instance_; }
 
+void DeviceDataManager::set_instance(DeviceDataManager* instance) {
+  CHECK(!instance_) << "Can not set multiple instances of DeviceDataManager";
+  instance_ = instance;
+}
+
 // static
 void DeviceDataManager::CreateInstance() {
   if (instance())
     return;
 
-  new DeviceDataManager();
+  set_instance(new DeviceDataManager());
+
+  base::AtExitManager::RegisterTask(base::Bind(DeleteInstance));
+}
+
+void DeviceDataManager::DeleteInstance() {
+  if (instance_) {
+    delete instance_;
+    instance_ = NULL;
+  }
 }
 
 // static
diff --git a/ui/events/devices/device_data_manager.h b/ui/events/devices/device_data_manager.h
index d8ede81..2975b9fe 100644
--- a/ui/events/devices/device_data_manager.h
+++ b/ui/events/devices/device_data_manager.h
@@ -30,6 +30,7 @@ class EVENTS_DEVICES_EXPORT DeviceDataManager
   ~DeviceDataManager() override;
 
   static void CreateInstance();
+  static void DeleteInstance();
   static DeviceDataManager* GetInstance();
   static bool HasInstance();
 
@@ -63,6 +64,8 @@ class EVENTS_DEVICES_EXPORT DeviceDataManager
 
   static DeviceDataManager* instance();
 
+  static void set_instance(DeviceDataManager* instance);
+
   // DeviceHotplugEventObserver:
   void OnTouchscreenDevicesUpdated(
       const std::vector<TouchscreenDevice>& devices) override;
diff --git a/ui/events/devices/x11/device_data_manager_x11.cc b/ui/events/devices/x11/device_data_manager_x11.cc
index 230b7fa..0f62b33 100644
--- a/ui/events/devices/x11/device_data_manager_x11.cc
+++ b/ui/events/devices/x11/device_data_manager_x11.cc
@@ -10,6 +10,8 @@
 
 #include <utility>
 
+#include "base/bind.h"
+#include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "base/memory/singleton.h"
 #include "base/sys_info.h"
@@ -130,7 +132,11 @@ void DeviceDataManagerX11::CreateInstance() {
   if (instance())
     return;
 
-  new DeviceDataManagerX11();
+  DeviceDataManagerX11* device_data_manager = new DeviceDataManagerX11();
+  base::AtExitManager::RegisterTask(
+      base::Bind(&base::DeletePointer<DeviceDataManager>, device_data_manager));
+
+  set_instance(device_data_manager);
 }
 
 // static