Add browser tests for USB device add/remove events.

These tests are essentially copies of the HID device add and remove
event tests. In order to reconcile issues with the MockUsbService
lifetime it is now tracked by a MessageLoop::DestructionObserver at the
generic UsbService level. This is similar to the pattern used by the
HidService until it was moved to the UI thread and could use a
LazyInstance.

BUG=411715

Review URL: https://codereview.chromium.org/800963005

Cr-Commit-Position: refs/heads/master@{#312538}

6 files changed, 198 insertions, 148 deletions

diff --git a/device/usb/BUILD.gn b/device/usb/BUILD.gn
index ee793d3..d4be7cf 100644
--- a/device/usb/BUILD.gn
+++ b/device/usb/BUILD.gn
@@ -25,8 +25,10 @@ source_set("usb") {
     "usb_error.h",
     "usb_ids.cc",
     "usb_ids.h",
+    "usb_service.cc",
     "usb_service.h",
     "usb_service_impl.cc",
+    "usb_service_impl.h",
     generated_ids,
   ]
 
diff --git a/device/usb/usb.gyp b/device/usb/usb.gyp
index 301bea9..c0995a1 100644
--- a/device/usb/usb.gyp
+++ b/device/usb/usb.gyp
@@ -34,8 +34,10 @@
         'usb_error.h',
         'usb_ids.cc',
         'usb_ids.h',
+        'usb_service.cc',
         'usb_service.h',
         'usb_service_impl.cc',
+        'usb_service_impl.h',
       ],
       'actions': [
         {
diff --git a/device/usb/usb_service.cc b/device/usb/usb_service.cc
new file mode 100644
index 0000000..70f054d
--- /dev/null
+++ b/device/usb/usb_service.cc
@@ -0,0 +1,90 @@
+// Copyright 2015 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 "device/usb/usb_service.h"
+
+#include "base/message_loop/message_loop.h"
+#include "device/usb/usb_device.h"
+#include "device/usb/usb_service_impl.h"
+
+namespace device {
+
+namespace {
+
+UsbService* g_service;
+
+}  // namespace
+
+// This class manages the lifetime of the global UsbService instance so that
+// it is destroyed when the current message loop is destroyed. A lazy instance
+// cannot be used because this object does not live on the main thread.
+class UsbService::Destroyer : private base::MessageLoop::DestructionObserver {
+ public:
+  explicit Destroyer(UsbService* usb_service) : usb_service_(usb_service) {
+    base::MessageLoop::current()->AddDestructionObserver(this);
+  }
+  ~Destroyer() override {}
+
+ private:
+  // base::MessageLoop::DestructionObserver implementation.
+  void WillDestroyCurrentMessageLoop() override {
+    base::MessageLoop::current()->RemoveDestructionObserver(this);
+    delete usb_service_;
+    delete this;
+    g_service = nullptr;
+  }
+
+  UsbService* usb_service_;
+};
+
+void UsbService::Observer::OnDeviceAdded(scoped_refptr<UsbDevice> device) {
+}
+
+void UsbService::Observer::OnDeviceRemoved(scoped_refptr<UsbDevice> device) {
+}
+
+// static
+UsbService* UsbService::GetInstance(
+    scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner) {
+  if (!g_service) {
+    g_service = UsbServiceImpl::Create(ui_task_runner);
+    // This object will clean itself up when the message loop is destroyed.
+    new Destroyer(g_service);
+  }
+  return g_service;
+}
+
+// static
+void UsbService::SetInstanceForTest(UsbService* instance) {
+  g_service = instance;
+  new Destroyer(instance);
+}
+
+UsbService::UsbService() {
+}
+
+UsbService::~UsbService() {
+}
+
+void UsbService::AddObserver(Observer* observer) {
+  DCHECK(CalledOnValidThread());
+  observer_list_.AddObserver(observer);
+}
+
+void UsbService::RemoveObserver(Observer* observer) {
+  DCHECK(CalledOnValidThread());
+  observer_list_.RemoveObserver(observer);
+}
+
+void UsbService::NotifyDeviceAdded(scoped_refptr<UsbDevice> device) {
+  DCHECK(CalledOnValidThread());
+  FOR_EACH_OBSERVER(Observer, observer_list_, OnDeviceAdded(device));
+}
+
+void UsbService::NotifyDeviceRemoved(scoped_refptr<UsbDevice> device) {
+  DCHECK(CalledOnValidThread());
+  FOR_EACH_OBSERVER(Observer, observer_list_, OnDeviceRemoved(device));
+}
+
+}  // namespace device
diff --git a/device/usb/usb_service.h b/device/usb/usb_service.h
index 076d363..4655bfd 100644
--- a/device/usb/usb_service.h
+++ b/device/usb/usb_service.h
@@ -55,8 +55,6 @@ class UsbService : public base::NonThreadSafe {
   void RemoveObserver(Observer* observer);
 
  protected:
-  friend struct base::DefaultDeleter<UsbService>;
-
   UsbService();
   virtual ~UsbService();
 
@@ -65,6 +63,9 @@ class UsbService : public base::NonThreadSafe {
 
   ObserverList<Observer, true> observer_list_;
 
+ private:
+  class Destroyer;
+
   DISALLOW_COPY_AND_ASSIGN(UsbService);
 };
 
diff --git a/device/usb/usb_service_impl.cc b/device/usb/usb_service_impl.cc
index 89fbd66a..d789e70 100644
--- a/device/usb/usb_service_impl.cc
+++ b/device/usb/usb_service_impl.cc
@@ -2,22 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "device/usb/usb_service.h"
+#include "device/usb/usb_service_impl.h"
 
-#include <map>
 #include <set>
 
 #include "base/bind.h"
-#include "base/lazy_instance.h"
+#include "base/location.h"
 #include "base/memory/weak_ptr.h"
-#include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/thread_task_runner_handle.h"
-#include "device/usb/usb_context.h"
-#include "device/usb/usb_device_impl.h"
 #include "device/usb/usb_error.h"
-#include "third_party/libusb/src/libusb/libusb.h"
 
 #if defined(OS_WIN)
 #include <usbiodef.h>
@@ -28,79 +23,6 @@
 
 namespace device {
 
-namespace {
-
-base::LazyInstance<scoped_ptr<UsbService> >::Leaky g_usb_service_instance =
-    LAZY_INSTANCE_INITIALIZER;
-
-}  // namespace
-
-typedef struct libusb_device* PlatformUsbDevice;
-typedef struct libusb_context* PlatformUsbContext;
-
-class UsbServiceImpl : public UsbService,
-                       private base::MessageLoop::DestructionObserver {
- public:
-  explicit UsbServiceImpl(
-      PlatformUsbContext context,
-      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
-  ~UsbServiceImpl() override;
-
- private:
-  // device::UsbService implementation
-  scoped_refptr<UsbDevice> GetDeviceById(uint32 unique_id) override;
-  void GetDevices(std::vector<scoped_refptr<UsbDevice>>* devices) override;
-
-  // base::MessageLoop::DestructionObserver implementation.
-  void WillDestroyCurrentMessageLoop() override;
-
-  // Enumerate USB devices from OS and update devices_ map.
-  void RefreshDevices();
-
-  // Adds a new UsbDevice to the devices_ map based on the given libusb device.
-  scoped_refptr<UsbDeviceImpl> AddDevice(PlatformUsbDevice platform_device);
-
-  // Handle hotplug events from libusb.
-  static int LIBUSB_CALL HotplugCallback(libusb_context* context,
-                                         PlatformUsbDevice device,
-                                         libusb_hotplug_event event,
-                                         void* user_data);
-  // These functions release a reference to the provided platform device.
-  void OnDeviceAdded(PlatformUsbDevice platform_device);
-  void OnDeviceRemoved(PlatformUsbDevice platform_device);
-
-  scoped_refptr<UsbContext> context_;
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
-  scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
-
-#if defined(OS_WIN)
-  class UIThreadHelper;
-  UIThreadHelper* ui_thread_helper_;
-#endif  // OS_WIN
-
-  // TODO(reillyg): Figure out a better solution for device IDs.
-  uint32 next_unique_id_;
-
-  // When available the device list will be updated when new devices are
-  // connected instead of only when a full enumeration is requested.
-  // TODO(reillyg): Support this on all platforms. crbug.com/411715
-  bool hotplug_enabled_;
-  libusb_hotplug_callback_handle hotplug_handle_;
-
-  // The map from unique IDs to UsbDevices.
-  typedef std::map<uint32, scoped_refptr<UsbDeviceImpl> > DeviceMap;
-  DeviceMap devices_;
-
-  // The map from PlatformUsbDevices to UsbDevices.
-  typedef std::map<PlatformUsbDevice, scoped_refptr<UsbDeviceImpl> >
-      PlatformDeviceMap;
-  PlatformDeviceMap platform_devices_;
-
-  base::WeakPtrFactory<UsbServiceImpl> weak_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(UsbServiceImpl);
-};
-
 #if defined(OS_WIN)
 // This class lives on the application main thread so that it can listen for
 // device change notification window messages. It registers for notifications
@@ -141,6 +63,23 @@ class UsbServiceImpl::UIThreadHelper final
 };
 #endif
 
+// static
+UsbService* UsbServiceImpl::Create(
+    scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner) {
+  PlatformUsbContext context = NULL;
+  const int rv = libusb_init(&context);
+  if (rv != LIBUSB_SUCCESS) {
+    VLOG(1) << "Failed to initialize libusb: "
+            << ConvertPlatformUsbErrorToString(rv);
+    return nullptr;
+  }
+  if (!context) {
+    return nullptr;
+  }
+
+  return new UsbServiceImpl(context, ui_task_runner);
+}
+
 scoped_refptr<UsbDevice> UsbServiceImpl::GetDeviceById(uint32 unique_id) {
   DCHECK(CalledOnValidThread());
   RefreshDevices();
@@ -165,11 +104,6 @@ void UsbServiceImpl::GetDevices(
   }
 }
 
-void UsbServiceImpl::WillDestroyCurrentMessageLoop() {
-  DCHECK(CalledOnValidThread());
-  g_usb_service_instance.Get().reset(NULL);
-}
-
 UsbServiceImpl::UsbServiceImpl(
     PlatformUsbContext context,
     scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner)
@@ -178,7 +112,6 @@ UsbServiceImpl::UsbServiceImpl(
       next_unique_id_(0),
       hotplug_enabled_(false),
       weak_factory_(this) {
-  base::MessageLoop::current()->AddDestructionObserver(this);
   task_runner_ = base::ThreadTaskRunnerHandle::Get();
   int rv = libusb_hotplug_register_callback(
       context_->context(),
@@ -200,7 +133,6 @@ UsbServiceImpl::UsbServiceImpl(
 }
 
 UsbServiceImpl::~UsbServiceImpl() {
-  base::MessageLoop::current()->RemoveDestructionObserver(this);
   if (hotplug_enabled_) {
     libusb_hotplug_deregister_callback(context_->context(), hotplug_handle_);
   }
@@ -356,63 +288,4 @@ void UsbServiceImpl::OnDeviceRemoved(PlatformUsbDevice platform_device) {
   libusb_unref_device(platform_device);
 }
 
-void UsbService::Observer::OnDeviceAdded(scoped_refptr<UsbDevice> device) {
-}
-
-void UsbService::Observer::OnDeviceRemoved(scoped_refptr<UsbDevice> device) {
-}
-
-// static
-UsbService* UsbService::GetInstance(
-    scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner) {
-  UsbService* instance = g_usb_service_instance.Get().get();
-  if (!instance) {
-    PlatformUsbContext context = NULL;
-
-    const int rv = libusb_init(&context);
-    if (rv != LIBUSB_SUCCESS) {
-      VLOG(1) << "Failed to initialize libusb: "
-              << ConvertPlatformUsbErrorToString(rv);
-      return NULL;
-    }
-    if (!context)
-      return NULL;
-
-    instance = new UsbServiceImpl(context, ui_task_runner);
-    g_usb_service_instance.Get().reset(instance);
-  }
-  return instance;
-}
-
-// static
-void UsbService::SetInstanceForTest(UsbService* instance) {
-  g_usb_service_instance.Get().reset(instance);
-}
-
-UsbService::UsbService() {
-}
-
-UsbService::~UsbService() {
-}
-
-void UsbService::AddObserver(Observer* observer) {
-  DCHECK(CalledOnValidThread());
-  observer_list_.AddObserver(observer);
-}
-
-void UsbService::RemoveObserver(Observer* observer) {
-  DCHECK(CalledOnValidThread());
-  observer_list_.RemoveObserver(observer);
-}
-
-void UsbService::NotifyDeviceAdded(scoped_refptr<UsbDevice> device) {
-  DCHECK(CalledOnValidThread());
-  FOR_EACH_OBSERVER(Observer, observer_list_, OnDeviceAdded(device));
-}
-
-void UsbService::NotifyDeviceRemoved(scoped_refptr<UsbDevice> device) {
-  DCHECK(CalledOnValidThread());
-  FOR_EACH_OBSERVER(Observer, observer_list_, OnDeviceRemoved(device));
-}
-
 }  // namespace device
diff --git a/device/usb/usb_service_impl.h b/device/usb/usb_service_impl.h
new file mode 100644
index 0000000..25cfb30
--- /dev/null
+++ b/device/usb/usb_service_impl.h
@@ -0,0 +1,82 @@
+// Copyright 2015 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 "device/usb/usb_service.h"
+
+#include <map>
+
+#include "base/memory/weak_ptr.h"
+#include "base/single_thread_task_runner.h"
+#include "device/usb/usb_context.h"
+#include "device/usb/usb_device_impl.h"
+#include "third_party/libusb/src/libusb/libusb.h"
+
+namespace device {
+
+typedef struct libusb_device* PlatformUsbDevice;
+typedef struct libusb_context* PlatformUsbContext;
+
+class UsbServiceImpl : public UsbService {
+ public:
+  static UsbService* Create(
+      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
+
+ private:
+  explicit UsbServiceImpl(
+      PlatformUsbContext context,
+      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
+  ~UsbServiceImpl() override;
+
+  // device::UsbService implementation
+  scoped_refptr<UsbDevice> GetDeviceById(uint32 unique_id) override;
+  void GetDevices(std::vector<scoped_refptr<UsbDevice>>* devices) override;
+
+  // Enumerate USB devices from OS and update devices_ map.
+  void RefreshDevices();
+
+  // Adds a new UsbDevice to the devices_ map based on the given libusb device.
+  scoped_refptr<UsbDeviceImpl> AddDevice(PlatformUsbDevice platform_device);
+
+  // Handle hotplug events from libusb.
+  static int LIBUSB_CALL HotplugCallback(libusb_context* context,
+                                         PlatformUsbDevice device,
+                                         libusb_hotplug_event event,
+                                         void* user_data);
+  // These functions release a reference to the provided platform device.
+  void OnDeviceAdded(PlatformUsbDevice platform_device);
+  void OnDeviceRemoved(PlatformUsbDevice platform_device);
+
+  scoped_refptr<UsbContext> context_;
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
+
+#if defined(OS_WIN)
+  class UIThreadHelper;
+  UIThreadHelper* ui_thread_helper_;
+#endif  // OS_WIN
+
+  // TODO(reillyg): Figure out a better solution for device IDs.
+  uint32 next_unique_id_;
+
+  // When available the device list will be updated when new devices are
+  // connected instead of only when a full enumeration is requested.
+  // TODO(reillyg): Support this on all platforms. crbug.com/411715
+  bool hotplug_enabled_;
+  libusb_hotplug_callback_handle hotplug_handle_;
+
+  // The map from unique IDs to UsbDevices.
+  typedef std::map<uint32, scoped_refptr<UsbDeviceImpl>> DeviceMap;
+  DeviceMap devices_;
+
+  // The map from PlatformUsbDevices to UsbDevices.
+  typedef std::map<PlatformUsbDevice, scoped_refptr<UsbDeviceImpl>>
+      PlatformDeviceMap;
+  PlatformDeviceMap platform_devices_;
+
+  base::WeakPtrFactory<UsbServiceImpl> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(UsbServiceImpl);
+};
+
+}  // namespace device