Create shared MockDeviceClient and MockHidService classes.

Both of these classes are redefined in multiple tests (and more tests I
have out for review) so this change unifies the definitions.

BUG=None

Review URL: https://codereview.chromium.org/1462793003

Cr-Commit-Position: refs/heads/master@{#361419}

25 files changed, 400 insertions, 340 deletions

diff --git a/chrome/browser/chrome_webusb_browser_client_unittest.cc b/chrome/browser/chrome_webusb_browser_client_unittest.cc
index 27cbe39..c2503d9 100644
--- a/chrome/browser/chrome_webusb_browser_client_unittest.cc
+++ b/chrome/browser/chrome_webusb_browser_client_unittest.cc
@@ -4,11 +4,13 @@
 
 #include "chrome/browser/chrome_webusb_browser_client.h"
 
+#include <string>
+
 #include "base/macros.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/webusb/webusb_detector.h"
-#include "device/core/device_client.h"
+#include "device/core/mock_device_client.h"
 #include "device/usb/mock_usb_device.h"
 #include "device/usb/mock_usb_service.h"
 #include "device/usb/usb_device.h"
@@ -31,19 +33,6 @@ const char* kLandingPage_1 = "https://www.google.com/A";
 const char* kLandingPage_2 = "https://www.google.com/B";
 const char* kLandingPage_3 = "https://www.google.com/C";
 
-class TestDeviceClient : public device::DeviceClient {
- public:
-  TestDeviceClient() : device::DeviceClient() {}
-  ~TestDeviceClient() override {}
-
-  device::MockUsbService& mock_usb_service() { return usb_service_; }
-
- private:
-  device::UsbService* GetUsbService() override { return &usb_service_; }
-
-  device::MockUsbService usb_service_;
-};
-
 }  // namespace
 
 class ChromeWebUsbBrowserClientTest : public testing::Test {
@@ -57,9 +46,10 @@ class ChromeWebUsbBrowserClientTest : public testing::Test {
   void TearDown() override { message_center::MessageCenter::Shutdown(); }
 
  protected:
-  TestDeviceClient device_client_;
+  device::MockDeviceClient device_client_;
   ChromeWebUsbBrowserClient chrome_webusb_browser_client_;
 
+ private:
   DISALLOW_COPY_AND_ASSIGN(ChromeWebUsbBrowserClientTest);
 };
 
@@ -71,7 +61,7 @@ TEST_F(ChromeWebUsbBrowserClientTest, UsbDeviceAddedAndRemoved) {
 
   webusb::WebUsbDetector webusb_detector(&chrome_webusb_browser_client_);
 
-  device_client_.mock_usb_service().AddDevice(device);
+  device_client_.usb_service()->AddDevice(device);
 
   message_center::MessageCenter* message_center =
       message_center::MessageCenter::Get();
@@ -91,7 +81,7 @@ TEST_F(ChromeWebUsbBrowserClientTest, UsbDeviceAddedAndRemoved) {
 
   EXPECT_TRUE(notification->delegate() != nullptr);
 
-  device_client_.mock_usb_service().RemoveDevice(device);
+  device_client_.usb_service()->RemoveDevice(device);
 
   // device is removed, so notification should be removed from the
   // message_center too
@@ -108,7 +98,7 @@ TEST_F(ChromeWebUsbBrowserClientTest,
 
   webusb::WebUsbDetector webusb_detector(&chrome_webusb_browser_client_);
 
-  device_client_.mock_usb_service().AddDevice(device);
+  device_client_.usb_service()->AddDevice(device);
 
   message_center::MessageCenter* message_center =
       message_center::MessageCenter::Get();
@@ -117,7 +107,7 @@ TEST_F(ChromeWebUsbBrowserClientTest,
   // for device without product name, no notification is generated
   EXPECT_EQ(nullptr, message_center->FindVisibleNotificationById(guid));
 
-  device_client_.mock_usb_service().RemoveDevice(device);
+  device_client_.usb_service()->RemoveDevice(device);
 
   EXPECT_EQ(nullptr, message_center->FindVisibleNotificationById(guid));
 }
@@ -131,7 +121,7 @@ TEST_F(ChromeWebUsbBrowserClientTest,
 
   webusb::WebUsbDetector webusb_detector(&chrome_webusb_browser_client_);
 
-  device_client_.mock_usb_service().AddDevice(device);
+  device_client_.usb_service()->AddDevice(device);
 
   message_center::MessageCenter* message_center =
       message_center::MessageCenter::Get();
@@ -140,7 +130,7 @@ TEST_F(ChromeWebUsbBrowserClientTest,
   // for device without landing page, no notification is generated
   EXPECT_EQ(nullptr, message_center->FindVisibleNotificationById(guid));
 
-  device_client_.mock_usb_service().RemoveDevice(device);
+  device_client_.usb_service()->RemoveDevice(device);
 
   EXPECT_EQ(nullptr, message_center->FindVisibleNotificationById(guid));
 }
@@ -159,7 +149,7 @@ TEST_F(ChromeWebUsbBrowserClientTest, UsbDeviceWasThereBeforeAndThenRemoved) {
 
   EXPECT_EQ(nullptr, message_center->FindVisibleNotificationById(guid));
 
-  device_client_.mock_usb_service().RemoveDevice(device);
+  device_client_.usb_service()->RemoveDevice(device);
 
   EXPECT_EQ(nullptr, message_center->FindVisibleNotificationById(guid));
 }
@@ -185,9 +175,9 @@ TEST_F(ChromeWebUsbBrowserClientTest, ThreeUsbDevicesAddedAndRemoved) {
 
   webusb::WebUsbDetector webusb_detector(&chrome_webusb_browser_client_);
 
-  device_client_.mock_usb_service().AddDevice(device_1);
-  device_client_.mock_usb_service().AddDevice(device_2);
-  device_client_.mock_usb_service().AddDevice(device_3);
+  device_client_.usb_service()->AddDevice(device_1);
+  device_client_.usb_service()->AddDevice(device_2);
+  device_client_.usb_service()->AddDevice(device_3);
 
   message_center::MessageCenter* message_center =
       message_center::MessageCenter::Get();
@@ -227,9 +217,9 @@ TEST_F(ChromeWebUsbBrowserClientTest, ThreeUsbDevicesAddedAndRemoved) {
   EXPECT_TRUE(notification_2->delegate() != nullptr);
   EXPECT_TRUE(notification_3->delegate() != nullptr);
 
-  device_client_.mock_usb_service().RemoveDevice(device_1);
-  device_client_.mock_usb_service().RemoveDevice(device_2);
-  device_client_.mock_usb_service().RemoveDevice(device_3);
+  device_client_.usb_service()->RemoveDevice(device_1);
+  device_client_.usb_service()->RemoveDevice(device_2);
+  device_client_.usb_service()->RemoveDevice(device_3);
 
   // devices are removed, so notifications should be removed from the
   // message_center too
diff --git a/chrome/browser/extensions/api/device_permissions_manager_unittest.cc b/chrome/browser/extensions/api/device_permissions_manager_unittest.cc
index 9863443..468aa5c 100644
--- a/chrome/browser/extensions/api/device_permissions_manager_unittest.cc
+++ b/chrome/browser/extensions/api/device_permissions_manager_unittest.cc
@@ -7,8 +7,9 @@
 #include "base/test/values_test_util.h"
 #include "chrome/browser/extensions/test_extension_environment.h"
 #include "chrome/test/base/testing_profile.h"
-#include "device/core/device_client.h"
+#include "device/core/mock_device_client.h"
 #include "device/hid/hid_device_info.h"
+#include "device/hid/mock_hid_service.h"
 #include "device/usb/mock_usb_device.h"
 #include "device/usb/mock_usb_service.h"
 #include "extensions/browser/api/device_permissions_manager.h"
@@ -21,14 +22,8 @@ namespace extensions {
 
 namespace {
 
-using device::HidDeviceId;
 using device::HidDeviceInfo;
-using device::HidService;
 using device::MockUsbDevice;
-using device::MockUsbService;
-using device::UsbDevice;
-using device::UsbDeviceHandle;
-using device::UsbService;
 using testing::_;
 using testing::DoAll;
 using testing::Return;
@@ -40,51 +35,6 @@ const uint64_t kTestDeviceIds[] = {1, 2, 3, 4};
 const char* kTestDeviceIds[] = {"A", "B", "C", "D"};
 #endif
 
-class MockDeviceClient : device::DeviceClient {
- public:
-  MockDeviceClient() {}
-
-  // device::DeviceClient implementation:
-  UsbService* GetUsbService() override {
-    DCHECK(usb_service_);
-    return usb_service_;
-  }
-
-  HidService* GetHidService() override {
-    DCHECK(hid_service_);
-    return hid_service_;
-  }
-
-  void set_usb_service(UsbService* service) { usb_service_ = service; }
-  void set_hid_service(HidService* service) { hid_service_ = service; }
-
- private:
-  UsbService* usb_service_ = nullptr;
-  HidService* hid_service_ = nullptr;
-};
-
-class MockHidService : public HidService {
- public:
-  MockHidService() {}
-  ~MockHidService() override {}
-
-  // Public wrappers around protected functions needed for tests.
-  void AddDevice(scoped_refptr<HidDeviceInfo> info) {
-    HidService::AddDevice(info);
-  }
-
-  void RemoveDevice(const HidDeviceId& device_id) {
-    HidService::RemoveDevice(device_id);
-  }
-
-  void FirstEnumerationComplete() { HidService::FirstEnumerationComplete(); }
-
- private:
-  MOCK_METHOD2(Connect,
-               void(const HidDeviceId& device_id,
-                    const ConnectCallback& callback));
-};
-
 }  // namespace
 
 class DevicePermissionsManagerTest : public testing::Test {
@@ -111,29 +61,25 @@ class DevicePermissionsManagerTest : public testing::Test {
     device4_ =
         new HidDeviceInfo(kTestDeviceIds[0], 0, 0, "Test HID Device", "abcde",
                           device::kHIDBusTypeUSB, std::vector<uint8>());
-    hid_service_.AddDevice(device4_);
+    device_client_.hid_service()->AddDevice(device4_);
     device5_ = new HidDeviceInfo(kTestDeviceIds[1], 0, 0, "Test HID Device", "",
                                  device::kHIDBusTypeUSB, std::vector<uint8>());
-    hid_service_.AddDevice(device5_);
+    device_client_.hid_service()->AddDevice(device5_);
     device6_ =
         new HidDeviceInfo(kTestDeviceIds[2], 0, 0, "Test HID Device", "67890",
                           device::kHIDBusTypeUSB, std::vector<uint8>());
-    hid_service_.AddDevice(device6_);
+    device_client_.hid_service()->AddDevice(device6_);
     device7_ = new HidDeviceInfo(kTestDeviceIds[3], 0, 0, "Test HID Device", "",
                                  device::kHIDBusTypeUSB, std::vector<uint8>());
-    hid_service_.AddDevice(device7_);
-    hid_service_.FirstEnumerationComplete();
-    mock_device_client_.set_usb_service(&usb_service_);
-    mock_device_client_.set_hid_service(&hid_service_);
+    device_client_.hid_service()->AddDevice(device7_);
+    device_client_.hid_service()->FirstEnumerationComplete();
   }
 
   void TearDown() override { env_.reset(nullptr); }
 
   scoped_ptr<extensions::TestExtensionEnvironment> env_;
   const extensions::Extension* extension_;
-  MockDeviceClient mock_device_client_;
-  MockUsbService usb_service_;
-  MockHidService hid_service_;
+  device::MockDeviceClient device_client_;
   scoped_refptr<MockUsbDevice> device0_;
   scoped_refptr<MockUsbDevice> device1_;
   scoped_refptr<MockUsbDevice> device2_;
@@ -231,10 +177,10 @@ TEST_F(DevicePermissionsManagerTest, DisconnectDevice) {
   EXPECT_FALSE(device_permissions->FindHidDeviceEntry(device6_).get());
   EXPECT_FALSE(device_permissions->FindHidDeviceEntry(device7_).get());
 
-  usb_service_.RemoveDevice(device0_);
-  usb_service_.RemoveDevice(device1_);
-  hid_service_.RemoveDevice(device4_->device_id());
-  hid_service_.RemoveDevice(device5_->device_id());
+  device_client_.usb_service()->RemoveDevice(device0_);
+  device_client_.usb_service()->RemoveDevice(device1_);
+  device_client_.hid_service()->RemoveDevice(device4_->device_id());
+  device_client_.hid_service()->RemoveDevice(device5_->device_id());
 
   // Device 0 will be accessible when it is reconnected because it can be
   // recognized by its serial number.
diff --git a/chrome/browser/usb/usb_chooser_context_unittest.cc b/chrome/browser/usb/usb_chooser_context_unittest.cc
index cab3408..57f7d6f 100644
--- a/chrome/browser/usb/usb_chooser_context_unittest.cc
+++ b/chrome/browser/usb/usb_chooser_context_unittest.cc
@@ -6,29 +6,11 @@
 #include "chrome/browser/usb/usb_chooser_context_factory.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/public/test/test_browser_thread_bundle.h"
-#include "device/core/device_client.h"
+#include "device/core/mock_device_client.h"
 #include "device/usb/mock_usb_device.h"
 #include "device/usb/mock_usb_service.h"
 
 using device::MockUsbDevice;
-using device::UsbDevice;
-
-namespace {
-
-class TestDeviceClient : public device::DeviceClient {
- public:
-  TestDeviceClient() {}
-  ~TestDeviceClient() override {}
-
-  device::MockUsbService& usb_service() { return usb_service_; }
-
- private:
-  device::UsbService* GetUsbService() override { return &usb_service_; }
-
-  device::MockUsbService usb_service_;
-};
-
-}  // namespace
 
 class UsbChooserContextTest : public testing::Test {
  public:
@@ -37,19 +19,19 @@ class UsbChooserContextTest : public testing::Test {
 
  protected:
   Profile* profile() { return &profile_; }
-  device::MockUsbService& usb_service() { return device_client_.usb_service(); }
+
+  device::MockDeviceClient device_client_;
 
  private:
   content::TestBrowserThreadBundle thread_bundle_;
-  TestDeviceClient device_client_;
   TestingProfile profile_;
 };
 
 TEST_F(UsbChooserContextTest, CheckGrantAndRevokePermission) {
   GURL origin("https://www.google.com");
-  scoped_refptr<UsbDevice> device =
+  scoped_refptr<MockUsbDevice> device =
       new MockUsbDevice(0, 0, "Google", "Gizmo", "123ABC");
-  usb_service().AddDevice(device);
+  device_client_.usb_service()->AddDevice(device);
   UsbChooserContext* store = UsbChooserContextFactory::GetForProfile(profile());
 
   EXPECT_FALSE(store->HasDevicePermission(origin, origin, device->guid()));
@@ -61,11 +43,11 @@ TEST_F(UsbChooserContextTest, CheckGrantAndRevokePermission) {
 
 TEST_F(UsbChooserContextTest, CheckGrantAndRevokeEphemeralPermission) {
   GURL origin("https://www.google.com");
-  scoped_refptr<UsbDevice> device =
+  scoped_refptr<MockUsbDevice> device =
       new MockUsbDevice(0, 0, "Google", "Gizmo", "");
-  scoped_refptr<UsbDevice> other_device =
+  scoped_refptr<MockUsbDevice> other_device =
       new MockUsbDevice(0, 0, "Google", "Gizmo", "");
-  usb_service().AddDevice(device);
+  device_client_.usb_service()->AddDevice(device);
   UsbChooserContext* store = UsbChooserContextFactory::GetForProfile(profile());
 
   EXPECT_FALSE(store->HasDevicePermission(origin, origin, device->guid()));
@@ -79,40 +61,40 @@ TEST_F(UsbChooserContextTest, CheckGrantAndRevokeEphemeralPermission) {
 
 TEST_F(UsbChooserContextTest, DisconnectDeviceWithPermission) {
   GURL origin("https://www.google.com");
-  scoped_refptr<UsbDevice> device =
+  scoped_refptr<MockUsbDevice> device =
       new MockUsbDevice(0, 0, "Google", "Gizmo", "123ABC");
-  usb_service().AddDevice(device);
+  device_client_.usb_service()->AddDevice(device);
   UsbChooserContext* store = UsbChooserContextFactory::GetForProfile(profile());
 
   EXPECT_FALSE(store->HasDevicePermission(origin, origin, device->guid()));
   store->GrantDevicePermission(origin, origin, device->guid());
   EXPECT_TRUE(store->HasDevicePermission(origin, origin, device->guid()));
-  usb_service().RemoveDevice(device);
+  device_client_.usb_service()->RemoveDevice(device);
   EXPECT_FALSE(store->HasDevicePermission(origin, origin, device->guid()));
 
-  scoped_refptr<UsbDevice> reconnected_device =
+  scoped_refptr<MockUsbDevice> reconnected_device =
       new MockUsbDevice(0, 0, "Google", "Gizmo", "123ABC");
-  usb_service().AddDevice(reconnected_device);
+  device_client_.usb_service()->AddDevice(reconnected_device);
   EXPECT_TRUE(
       store->HasDevicePermission(origin, origin, reconnected_device->guid()));
 }
 
 TEST_F(UsbChooserContextTest, DisconnectDeviceWithEphemeralPermission) {
   GURL origin("https://www.google.com");
-  scoped_refptr<UsbDevice> device =
+  scoped_refptr<MockUsbDevice> device =
       new MockUsbDevice(0, 0, "Google", "Gizmo", "");
-  usb_service().AddDevice(device);
+  device_client_.usb_service()->AddDevice(device);
   UsbChooserContext* store = UsbChooserContextFactory::GetForProfile(profile());
 
   EXPECT_FALSE(store->HasDevicePermission(origin, origin, device->guid()));
   store->GrantDevicePermission(origin, origin, device->guid());
   EXPECT_TRUE(store->HasDevicePermission(origin, origin, device->guid()));
-  usb_service().RemoveDevice(device);
+  device_client_.usb_service()->RemoveDevice(device);
   EXPECT_FALSE(store->HasDevicePermission(origin, origin, device->guid()));
 
-  scoped_refptr<UsbDevice> reconnected_device =
+  scoped_refptr<MockUsbDevice> reconnected_device =
       new MockUsbDevice(0, 0, "Google", "Gizmo", "");
-  usb_service().AddDevice(reconnected_device);
+  device_client_.usb_service()->AddDevice(reconnected_device);
   EXPECT_FALSE(
       store->HasDevicePermission(origin, origin, reconnected_device->guid()));
 }
diff --git a/chrome/chrome_tests_unit.gypi b/chrome/chrome_tests_unit.gypi
index fb2bf38..f4fc12c 100644
--- a/chrome/chrome_tests_unit.gypi
+++ b/chrome/chrome_tests_unit.gypi
@@ -2337,6 +2337,8 @@
           'sources': [ '<@(chrome_unit_tests_extensions_sources)' ],
           'dependencies': [
             'common/extensions/api/api.gyp:chrome_api',
+            '../device/core/core.gyp:device_core_mocks',
+            '../device/hid/hid.gyp:device_hid_mocks',
             '../device/usb/usb.gyp:device_usb_mocks',
             '../components/components.gyp:audio_modem_test_support',
             '../extensions/extensions_resources.gyp:extensions_resources',
diff --git a/chrome/test/BUILD.gn b/chrome/test/BUILD.gn
index 38f4bfb..4b40d69 100644
--- a/chrome/test/BUILD.gn
+++ b/chrome/test/BUILD.gn
@@ -1592,6 +1592,7 @@ test("unit_tests") {
       "//components/webdata_services:test_support",
       "//content/app/resources",
       "//device/bluetooth:mocks",
+      "//device/core:mocks",
       "//gpu:test_support",
       "//media:test_support",
 
diff --git a/components/components_tests.gyp b/components/components_tests.gyp
index 2a5c13b..5fcd7b3 100644
--- a/components/components_tests.gyp
+++ b/components/components_tests.gyp
@@ -1345,6 +1345,8 @@
           'dependencies': [
             '../device/bluetooth/bluetooth.gyp:device_bluetooth_mocks',
             '../device/core/core.gyp:device_core',
+            '../device/core/core.gyp:device_core_mocks',
+            '../device/hid/hid.gyp:device_hid_mocks',
             '../device/usb/usb.gyp:device_usb',
             '../device/usb/usb.gyp:device_usb_mocks',
             '../google_apis/google_apis.gyp:google_apis_test_support',
diff --git a/components/webusb/BUILD.gn b/components/webusb/BUILD.gn
index 0a7d1fe..f62a2ea 100644
--- a/components/webusb/BUILD.gn
+++ b/components/webusb/BUILD.gn
@@ -27,6 +27,7 @@ source_set("unit_tests") {
     ":webusb",
     "//base",
     "//device/core",
+    "//device/core:mocks",
     "//device/usb",
     "//device/usb:mocks",
     "//testing/gmock",
diff --git a/components/webusb/webusb_detector_unittest.cc b/components/webusb/webusb_detector_unittest.cc
index 6b6e4d3..eebede8 100644
--- a/components/webusb/webusb_detector_unittest.cc
+++ b/components/webusb/webusb_detector_unittest.cc
@@ -4,15 +4,15 @@
 
 #include "components/webusb/webusb_detector.h"
 
+#include <string>
+
 #include "base/macros.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/webusb/webusb_browser_client.h"
-#include "device/core/device_client.h"
+#include "device/core/mock_device_client.h"
 #include "device/usb/mock_usb_device.h"
 #include "device/usb/mock_usb_service.h"
-#include "device/usb/usb_device.h"
-#include "device/usb/usb_service.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
@@ -35,19 +35,6 @@ namespace webusb {
 
 namespace {
 
-class TestDeviceClient : public device::DeviceClient {
- public:
-  TestDeviceClient() : device::DeviceClient() {}
-  ~TestDeviceClient() override {}
-
-  device::MockUsbService& mock_usb_service() { return usb_service_; }
-
- private:
-  device::UsbService* GetUsbService() override { return &usb_service_; }
-
-  device::MockUsbService usb_service_;
-};
-
 class MockWebUsbBrowserClient : public webusb::WebUsbBrowserClient {
  public:
   MockWebUsbBrowserClient() {}
@@ -76,9 +63,10 @@ class WebUsbDetectorTest : public testing::Test {
   ~WebUsbDetectorTest() override = default;
 
  protected:
-  TestDeviceClient device_client_;
+  device::MockDeviceClient device_client_;
   MockWebUsbBrowserClient mock_webusb_browser_client_;
 
+ private:
   DISALLOW_COPY_AND_ASSIGN(WebUsbDetectorTest);
 };
 
@@ -97,7 +85,7 @@ TEST_F(WebUsbDetectorTest, UsbDeviceAdded) {
 
   webusb::WebUsbDetector webusb_detector(&mock_webusb_browser_client_);
 
-  device_client_.mock_usb_service().AddDevice(device);
+  device_client_.usb_service()->AddDevice(device);
 }
 
 TEST_F(WebUsbDetectorTest, UsbDeviceAddedAndRemoved) {
@@ -117,8 +105,8 @@ TEST_F(WebUsbDetectorTest, UsbDeviceAddedAndRemoved) {
 
   webusb::WebUsbDetector webusb_detector(&mock_webusb_browser_client_);
 
-  device_client_.mock_usb_service().AddDevice(device);
-  device_client_.mock_usb_service().RemoveDevice(device);
+  device_client_.usb_service()->AddDevice(device);
+  device_client_.usb_service()->RemoveDevice(device);
 }
 
 TEST_F(WebUsbDetectorTest, UsbDeviceWithoutProductNameAddedAndRemoved) {
@@ -135,8 +123,8 @@ TEST_F(WebUsbDetectorTest, UsbDeviceWithoutProductNameAddedAndRemoved) {
 
   webusb::WebUsbDetector webusb_detector(&mock_webusb_browser_client_);
 
-  device_client_.mock_usb_service().AddDevice(device);
-  device_client_.mock_usb_service().RemoveDevice(device);
+  device_client_.usb_service()->AddDevice(device);
+  device_client_.usb_service()->RemoveDevice(device);
 }
 
 TEST_F(WebUsbDetectorTest, UsbDeviceWithoutLandingPageAddedAndRemoved) {
@@ -152,8 +140,8 @@ TEST_F(WebUsbDetectorTest, UsbDeviceWithoutLandingPageAddedAndRemoved) {
 
   webusb::WebUsbDetector webusb_detector(&mock_webusb_browser_client_);
 
-  device_client_.mock_usb_service().AddDevice(device);
-  device_client_.mock_usb_service().RemoveDevice(device);
+  device_client_.usb_service()->AddDevice(device);
+  device_client_.usb_service()->RemoveDevice(device);
 }
 
 TEST_F(WebUsbDetectorTest, WebUsbBrowserClientIsNullptr) {
@@ -169,8 +157,8 @@ TEST_F(WebUsbDetectorTest, WebUsbBrowserClientIsNullptr) {
 
   webusb::WebUsbDetector webusb_detector(nullptr);
 
-  device_client_.mock_usb_service().AddDevice(device);
-  device_client_.mock_usb_service().RemoveDevice(device);
+  device_client_.usb_service()->AddDevice(device);
+  device_client_.usb_service()->RemoveDevice(device);
 }
 
 TEST_F(WebUsbDetectorTest, NoUsbService) {
@@ -199,11 +187,11 @@ TEST_F(WebUsbDetectorTest, UsbDeviceWasThereBeforeAndThenRemoved) {
   EXPECT_CALL(mock_webusb_browser_client_, OnDeviceRemoved(guid)).Times(1);
 
   // usb device was added before webusb_detector was created
-  device_client_.mock_usb_service().AddDevice(device);
+  device_client_.usb_service()->AddDevice(device);
 
   webusb::WebUsbDetector webusb_detector(&mock_webusb_browser_client_);
 
-  device_client_.mock_usb_service().RemoveDevice(device);
+  device_client_.usb_service()->RemoveDevice(device);
 }
 
 TEST_F(
@@ -243,13 +231,13 @@ TEST_F(
 
   // three usb devices were added and removed before webusb_detector was
   // created
-  device_client_.mock_usb_service().AddDevice(device_1);
-  device_client_.mock_usb_service().AddDevice(device_2);
-  device_client_.mock_usb_service().AddDevice(device_3);
+  device_client_.usb_service()->AddDevice(device_1);
+  device_client_.usb_service()->AddDevice(device_2);
+  device_client_.usb_service()->AddDevice(device_3);
 
-  device_client_.mock_usb_service().RemoveDevice(device_1);
-  device_client_.mock_usb_service().RemoveDevice(device_2);
-  device_client_.mock_usb_service().RemoveDevice(device_3);
+  device_client_.usb_service()->RemoveDevice(device_1);
+  device_client_.usb_service()->RemoveDevice(device_2);
+  device_client_.usb_service()->RemoveDevice(device_3);
 
   webusb::WebUsbDetector webusb_detector(&mock_webusb_browser_client_);
 }
@@ -294,15 +282,15 @@ TEST_F(
   }
 
   // three usb devices were added before webusb_detector was created
-  device_client_.mock_usb_service().AddDevice(device_1);
-  device_client_.mock_usb_service().AddDevice(device_2);
-  device_client_.mock_usb_service().AddDevice(device_3);
+  device_client_.usb_service()->AddDevice(device_1);
+  device_client_.usb_service()->AddDevice(device_2);
+  device_client_.usb_service()->AddDevice(device_3);
 
   webusb::WebUsbDetector webusb_detector(&mock_webusb_browser_client_);
 
-  device_client_.mock_usb_service().RemoveDevice(device_1);
-  device_client_.mock_usb_service().RemoveDevice(device_2);
-  device_client_.mock_usb_service().RemoveDevice(device_3);
+  device_client_.usb_service()->RemoveDevice(device_1);
+  device_client_.usb_service()->RemoveDevice(device_2);
+  device_client_.usb_service()->RemoveDevice(device_3);
 }
 
 TEST_F(WebUsbDetectorTest,
@@ -344,15 +332,15 @@ TEST_F(WebUsbDetectorTest,
   }
 
   // two usb devices were added before webusb_detector was created
-  device_client_.mock_usb_service().AddDevice(device_1);
-  device_client_.mock_usb_service().AddDevice(device_3);
+  device_client_.usb_service()->AddDevice(device_1);
+  device_client_.usb_service()->AddDevice(device_3);
 
   webusb::WebUsbDetector webusb_detector(&mock_webusb_browser_client_);
 
-  device_client_.mock_usb_service().RemoveDevice(device_1);
-  device_client_.mock_usb_service().AddDevice(device_2);
-  device_client_.mock_usb_service().RemoveDevice(device_3);
-  device_client_.mock_usb_service().RemoveDevice(device_2);
+  device_client_.usb_service()->RemoveDevice(device_1);
+  device_client_.usb_service()->AddDevice(device_2);
+  device_client_.usb_service()->RemoveDevice(device_3);
+  device_client_.usb_service()->RemoveDevice(device_2);
 }
 
 TEST_F(WebUsbDetectorTest, ThreeUsbDevicesAddedAndRemoved) {
@@ -395,12 +383,12 @@ TEST_F(WebUsbDetectorTest, ThreeUsbDevicesAddedAndRemoved) {
 
   webusb::WebUsbDetector webusb_detector(&mock_webusb_browser_client_);
 
-  device_client_.mock_usb_service().AddDevice(device_1);
-  device_client_.mock_usb_service().RemoveDevice(device_1);
-  device_client_.mock_usb_service().AddDevice(device_2);
-  device_client_.mock_usb_service().RemoveDevice(device_2);
-  device_client_.mock_usb_service().AddDevice(device_3);
-  device_client_.mock_usb_service().RemoveDevice(device_3);
+  device_client_.usb_service()->AddDevice(device_1);
+  device_client_.usb_service()->RemoveDevice(device_1);
+  device_client_.usb_service()->AddDevice(device_2);
+  device_client_.usb_service()->RemoveDevice(device_2);
+  device_client_.usb_service()->AddDevice(device_3);
+  device_client_.usb_service()->RemoveDevice(device_3);
 }
 
 TEST_F(WebUsbDetectorTest, ThreeUsbDeviceAddedAndRemovedDifferentOrder) {
@@ -446,12 +434,12 @@ TEST_F(WebUsbDetectorTest, ThreeUsbDeviceAddedAndRemovedDifferentOrder) {
 
   webusb::WebUsbDetector webusb_detector(&mock_webusb_browser_client_);
 
-  device_client_.mock_usb_service().AddDevice(device_1);
-  device_client_.mock_usb_service().AddDevice(device_2);
-  device_client_.mock_usb_service().RemoveDevice(device_2);
-  device_client_.mock_usb_service().AddDevice(device_3);
-  device_client_.mock_usb_service().RemoveDevice(device_1);
-  device_client_.mock_usb_service().RemoveDevice(device_3);
+  device_client_.usb_service()->AddDevice(device_1);
+  device_client_.usb_service()->AddDevice(device_2);
+  device_client_.usb_service()->RemoveDevice(device_2);
+  device_client_.usb_service()->AddDevice(device_3);
+  device_client_.usb_service()->RemoveDevice(device_1);
+  device_client_.usb_service()->RemoveDevice(device_3);
 }
 
 }  // namespace webusb
diff --git a/device/BUILD.gn b/device/BUILD.gn
index 1a72de1..e4f56a5 100644
--- a/device/BUILD.gn
+++ b/device/BUILD.gn
@@ -123,6 +123,7 @@ test("device_unittests") {
     ]
     deps += [
       "//device/core",
+      "//device/core:mocks",
       "//device/devices_app:lib",
       "//device/devices_app/usb/public/interfaces",
       "//device/usb",
diff --git a/device/core/BUILD.gn b/device/core/BUILD.gn
index b7e6ac2..9aaf280 100644
--- a/device/core/BUILD.gn
+++ b/device/core/BUILD.gn
@@ -24,3 +24,18 @@ component("core") {
     libs = [ "setupapi.lib" ]
   }
 }
+
+source_set("mocks") {
+  testonly = true
+
+  sources = [
+    "mock_device_client.cc",
+    "mock_device_client.h",
+  ]
+
+  deps = [
+    ":core",
+    "//device/hid:mocks",
+    "//device/usb:mocks",
+  ]
+}
diff --git a/device/core/core.gyp b/device/core/core.gyp
index 6002a5f..19754cb 100644
--- a/device/core/core.gyp
+++ b/device/core/core.gyp
@@ -28,5 +28,20 @@
         '../../base/base.gyp:base',
       ]
     },
+    {
+      'target_name': 'device_core_mocks',
+      'type': 'static_library',
+      'include_dirs': [
+        '../..',
+      ],
+      'dependencies': [
+        '../../testing/gmock.gyp:gmock',
+        'device_core',
+      ],
+      'sources': [
+        'mock_device_client.cc',
+        'mock_device_client.h',
+      ],
+    },
   ],
 }
diff --git a/device/core/mock_device_client.cc b/device/core/mock_device_client.cc
new file mode 100644
index 0000000..8e82c37
--- /dev/null
+++ b/device/core/mock_device_client.cc
@@ -0,0 +1,36 @@
+// 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/core/mock_device_client.h"
+
+#include "device/hid/mock_hid_service.h"
+#include "device/usb/mock_usb_service.h"
+
+namespace device {
+
+MockDeviceClient::MockDeviceClient() {}
+
+MockDeviceClient::~MockDeviceClient() {}
+
+HidService* MockDeviceClient::GetHidService() {
+  return hid_service();
+}
+
+UsbService* MockDeviceClient::GetUsbService() {
+  return usb_service();
+}
+
+MockHidService* MockDeviceClient::hid_service() {
+  if (!hid_service_)
+    hid_service_.reset(new MockHidService());
+  return hid_service_.get();
+}
+
+MockUsbService* MockDeviceClient::usb_service() {
+  if (!usb_service_)
+    usb_service_.reset(new MockUsbService());
+  return usb_service_.get();
+}
+
+}  // namespace device
diff --git a/device/core/mock_device_client.h b/device/core/mock_device_client.h
new file mode 100644
index 0000000..e085c63
--- /dev/null
+++ b/device/core/mock_device_client.h
@@ -0,0 +1,38 @@
+// 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.
+
+#ifndef DEVICE_CORE_MOCK_DEVICE_CLIENT_H_
+#define DEVICE_CORE_MOCK_DEVICE_CLIENT_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "device/core/device_client.h"
+
+namespace device {
+
+class HidService;
+class MockHidService;
+class MockUsbService;
+class UsbService;
+
+class MockDeviceClient : device::DeviceClient {
+ public:
+  MockDeviceClient();
+  ~MockDeviceClient() override;
+
+  // device::DeviceClient implementation:
+  UsbService* GetUsbService() override;
+  HidService* GetHidService() override;
+
+  // Accessors for the mock instances.
+  MockHidService* hid_service();
+  MockUsbService* usb_service();
+
+ private:
+  scoped_ptr<MockHidService> hid_service_;
+  scoped_ptr<MockUsbService> usb_service_;
+};
+
+}  // namespace device
+
+#endif  // DEVICE_CORE_MOCK_DEVICE_CLIENT_H_
diff --git a/device/device_tests.gyp b/device/device_tests.gyp
index c0915ff..a3fc8c6 100644
--- a/device/device_tests.gyp
+++ b/device/device_tests.gyp
@@ -23,11 +23,13 @@
         'bluetooth/bluetooth.gyp:device_bluetooth',
         'bluetooth/bluetooth.gyp:device_bluetooth_mocks',
         'core/core.gyp:device_core',
+        'core/core.gyp:device_core_mocks',
         'devices_app/devices_app.gyp:devices_app_lib',
         'nfc/nfc.gyp:device_nfc',
         'usb/usb.gyp:device_usb',
         'usb/usb.gyp:device_usb_mocks',
         'hid/hid.gyp:device_hid',
+        'hid/hid.gyp:device_hid_mocks',
         'serial/serial.gyp:device_serial',
         'serial/serial.gyp:device_serial_test_util',
       ],
diff --git a/device/devices_app/usb/device_manager_impl_unittest.cc b/device/devices_app/usb/device_manager_impl_unittest.cc
index ca7e0bd..6ab03f6 100644
--- a/device/devices_app/usb/device_manager_impl_unittest.cc
+++ b/device/devices_app/usb/device_manager_impl_unittest.cc
@@ -11,7 +11,7 @@
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/thread_task_runner_handle.h"
-#include "device/core/device_client.h"
+#include "device/core/mock_device_client.h"
 #include "device/devices_app/usb/device_impl.h"
 #include "device/devices_app/usb/device_manager_impl.h"
 #include "device/devices_app/usb/fake_permission_provider.h"
@@ -28,32 +28,12 @@ namespace usb {
 
 namespace {
 
-class TestDeviceClient : public DeviceClient {
- public:
-  TestDeviceClient() {}
-  ~TestDeviceClient() override {}
-
-  MockUsbService& mock_usb_service() { return mock_usb_service_; }
-
- private:
-  // DeviceClient implementation:
-  UsbService* GetUsbService() override { return &mock_usb_service_; }
-
-  MockUsbService mock_usb_service_;
-};
-
 class USBDeviceManagerImplTest : public testing::Test {
  public:
-  USBDeviceManagerImplTest()
-      : device_client_(new TestDeviceClient),
-        message_loop_(new base::MessageLoop) {}
+  USBDeviceManagerImplTest() : message_loop_(new base::MessageLoop) {}
   ~USBDeviceManagerImplTest() override {}
 
  protected:
-  MockUsbService& mock_usb_service() {
-    return device_client_->mock_usb_service();
-  }
-
   DeviceManagerPtr ConnectToDeviceManager() {
     PermissionProviderPtr permission_provider;
     permission_provider_.Bind(mojo::GetProxy(&permission_provider));
@@ -63,9 +43,10 @@ class USBDeviceManagerImplTest : public testing::Test {
     return device_manager.Pass();
   }
 
+  MockDeviceClient device_client_;
+
  private:
   FakePermissionProvider permission_provider_;
-  scoped_ptr<TestDeviceClient> device_client_;
   scoped_ptr<base::MessageLoop> message_loop_;
 };
 
@@ -118,9 +99,9 @@ TEST_F(USBDeviceManagerImplTest, GetDevices) {
   scoped_refptr<MockUsbDevice> device2 =
       new MockUsbDevice(0x1234, 0x567a, "ACME", "Frobinator Mk II", "MNOPQR");
 
-  mock_usb_service().AddDevice(device0);
-  mock_usb_service().AddDevice(device1);
-  mock_usb_service().AddDevice(device2);
+  device_client_.usb_service()->AddDevice(device0);
+  device_client_.usb_service()->AddDevice(device1);
+  device_client_.usb_service()->AddDevice(device2);
 
   DeviceManagerPtr device_manager = ConnectToDeviceManager();
 
@@ -147,7 +128,7 @@ TEST_F(USBDeviceManagerImplTest, GetDevice) {
   scoped_refptr<MockUsbDevice> mock_device =
       new MockUsbDevice(0x1234, 0x5678, "ACME", "Frobinator", "ABCDEF");
 
-  mock_usb_service().AddDevice(mock_device);
+  device_client_.usb_service()->AddDevice(mock_device);
 
   DeviceManagerPtr device_manager = ConnectToDeviceManager();
 
@@ -181,7 +162,7 @@ TEST_F(USBDeviceManagerImplTest, GetDeviceChanges) {
   scoped_refptr<MockUsbDevice> device3 =
       new MockUsbDevice(0x1234, 0x567b, "ACME", "Frobinator Xtreme", "STUVWX");
 
-  mock_usb_service().AddDevice(device0);
+  device_client_.usb_service()->AddDevice(device0);
 
   DeviceManagerPtr device_manager = ConnectToDeviceManager();
 
@@ -197,9 +178,9 @@ TEST_F(USBDeviceManagerImplTest, GetDeviceChanges) {
     loop.Run();
   }
 
-  mock_usb_service().AddDevice(device1);
-  mock_usb_service().AddDevice(device2);
-  mock_usb_service().RemoveDevice(device1);
+  device_client_.usb_service()->AddDevice(device1);
+  device_client_.usb_service()->AddDevice(device2);
+  device_client_.usb_service()->RemoveDevice(device1);
 
   {
     std::set<std::string> added_guids;
@@ -212,9 +193,9 @@ TEST_F(USBDeviceManagerImplTest, GetDeviceChanges) {
     loop.Run();
   }
 
-  mock_usb_service().RemoveDevice(device0);
-  mock_usb_service().RemoveDevice(device2);
-  mock_usb_service().AddDevice(device3);
+  device_client_.usb_service()->RemoveDevice(device0);
+  device_client_.usb_service()->RemoveDevice(device2);
+  device_client_.usb_service()->AddDevice(device3);
 
   {
     std::set<std::string> added_guids;
diff --git a/device/hid/BUILD.gn b/device/hid/BUILD.gn
index 9288f70..4270ce8 100644
--- a/device/hid/BUILD.gn
+++ b/device/hid/BUILD.gn
@@ -61,3 +61,17 @@ source_set("hid") {
     deps += [ "//chromeos" ]
   }
 }
+
+source_set("mocks") {
+  testonly = true
+
+  sources = [
+    "mock_hid_service.cc",
+    "mock_hid_service.h",
+  ]
+
+  public_deps = [
+    ":hid",
+    "//testing/gmock",
+  ]
+}
diff --git a/device/hid/hid.gyp b/device/hid/hid.gyp
index f7a0baf..2d0169b 100644
--- a/device/hid/hid.gyp
+++ b/device/hid/hid.gyp
@@ -66,5 +66,20 @@
         }],
       ],
     },
+    {
+      'target_name': 'device_hid_mocks',
+      'type': 'static_library',
+      'include_dirs': [
+        '../..',
+      ],
+      'dependencies': [
+        '../../testing/gmock.gyp:gmock',
+        'device_hid',
+      ],
+      'sources': [
+        'mock_hid_service.cc',
+        'mock_hid_service.h',
+      ],
+    },
   ],
 }
diff --git a/device/hid/mock_hid_service.cc b/device/hid/mock_hid_service.cc
new file mode 100644
index 0000000..7c73a35
--- /dev/null
+++ b/device/hid/mock_hid_service.cc
@@ -0,0 +1,30 @@
+// 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/hid/mock_hid_service.h"
+
+namespace device {
+
+MockHidService::MockHidService() {}
+
+MockHidService::~MockHidService() {}
+
+void MockHidService::AddDevice(scoped_refptr<HidDeviceInfo> info) {
+  HidService::AddDevice(info);
+}
+
+void MockHidService::RemoveDevice(const HidDeviceId& device_id) {
+  HidService::RemoveDevice(device_id);
+}
+
+void MockHidService::FirstEnumerationComplete() {
+  HidService::FirstEnumerationComplete();
+}
+
+const std::map<HidDeviceId, scoped_refptr<HidDeviceInfo>>&
+MockHidService::devices() const {
+  return HidService::devices();
+}
+
+}  // namespace device
diff --git a/device/hid/mock_hid_service.h b/device/hid/mock_hid_service.h
new file mode 100644
index 0000000..f5f6c82
--- /dev/null
+++ b/device/hid/mock_hid_service.h
@@ -0,0 +1,33 @@
+// 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.
+
+#ifndef DEVICE_HID_MOCK_HID_SERVICE_H_
+#define DEVICE_HID_MOCK_HID_SERVICE_H_
+
+#include <map>
+
+#include "device/hid/hid_service.h"
+#include "testing/gmock/include/gmock/gmock.h"
+
+namespace device {
+
+class MockHidService : public HidService {
+ public:
+  MockHidService();
+  ~MockHidService() override;
+
+  // Public wrappers around protected functions needed for tests.
+  void AddDevice(scoped_refptr<HidDeviceInfo> info);
+  void RemoveDevice(const HidDeviceId& device_id);
+  void FirstEnumerationComplete();
+  const std::map<HidDeviceId, scoped_refptr<HidDeviceInfo>>& devices() const;
+
+  MOCK_METHOD2(Connect,
+               void(const HidDeviceId& device_id,
+                    const ConnectCallback& callback));
+};
+
+}  // namespace device
+
+#endif  // DEVICE_HID_MOCK_HID_SERVICE_H_
diff --git a/device/usb/BUILD.gn b/device/usb/BUILD.gn
index 6d17f7d..99e12ca 100644
--- a/device/usb/BUILD.gn
+++ b/device/usb/BUILD.gn
@@ -86,6 +86,9 @@ source_set("mocks") {
   deps = [
     ":usb",
     "//base",
+  ]
+
+  public_deps = [
     "//testing/gmock",
   ]
 }
diff --git a/device/usb/mock_usb_service.cc b/device/usb/mock_usb_service.cc
index f9bf9d9..6a205fc 100644
--- a/device/usb/mock_usb_service.cc
+++ b/device/usb/mock_usb_service.cc
@@ -4,6 +4,9 @@
 
 #include "device/usb/mock_usb_service.h"
 
+#include <string>
+#include <vector>
+
 #include "device/usb/usb_device.h"
 
 namespace device {
@@ -33,9 +36,8 @@ scoped_refptr<UsbDevice> MockUsbService::GetDevice(const std::string& guid) {
 
 void MockUsbService::GetDevices(const GetDevicesCallback& callback) {
   std::vector<scoped_refptr<UsbDevice>> devices;
-  for (const auto& map_entry : devices_) {
+  for (const auto& map_entry : devices_)
     devices.push_back(map_entry.second);
-  }
   callback.Run(devices);
 }
 
diff --git a/extensions/BUILD.gn b/extensions/BUILD.gn
index 1a86e84..ca739a1 100644
--- a/extensions/BUILD.gn
+++ b/extensions/BUILD.gn
@@ -260,6 +260,8 @@ test("extensions_browsertests") {
     "//components/storage_monitor:test_support",
     "//content/test:test_support",
     "//device/bluetooth:mocks",
+    "//device/core:mocks",
+    "//device/hid:mocks",
     "//device/usb:mocks",
     "//mojo/environment:chromium",
     "//mojo/public/cpp/bindings",
diff --git a/extensions/browser/api/hid/hid_apitest.cc b/extensions/browser/api/hid/hid_apitest.cc
index 1e35ecd..955c67c 100644
--- a/extensions/browser/api/hid/hid_apitest.cc
+++ b/extensions/browser/api/hid/hid_apitest.cc
@@ -5,12 +5,12 @@
 #include "base/bind.h"
 #include "base/run_loop.h"
 #include "base/thread_task_runner_handle.h"
-#include "device/core/device_client.h"
+#include "device/core/mock_device_client.h"
 #include "device/hid/hid_collection_info.h"
 #include "device/hid/hid_connection.h"
 #include "device/hid/hid_device_info.h"
-#include "device/hid/hid_service.h"
 #include "device/hid/hid_usage_and_page.h"
+#include "device/hid/mock_hid_service.h"
 #include "extensions/browser/api/device_permissions_prompt.h"
 #include "extensions/shell/browser/shell_extensions_api_client.h"
 #include "extensions/shell/test/shell_apitest.h"
@@ -19,12 +19,12 @@
 
 using base::ThreadTaskRunnerHandle;
 using device::HidCollectionInfo;
-using device::HidConnection;
 using device::HidDeviceId;
 using device::HidDeviceInfo;
-using device::HidService;
 using device::HidUsageAndPage;
+using device::MockDeviceClient;
 using net::IOBuffer;
+using testing::_;
 
 #if defined(OS_MACOSX)
 const uint64_t kTestDeviceIds[] = {1, 2, 3, 4, 5};
@@ -32,8 +32,6 @@ const uint64_t kTestDeviceIds[] = {1, 2, 3, 4, 5};
 const char* kTestDeviceIds[] = {"A", "B", "C", "D", "E"};
 #endif
 
-namespace device {
-
 // These report descriptors define two devices with 8-byte input, output and
 // feature reports. The first implements usage page 0xFF00 and has a single
 // report without and ID. The second implements usage page 0xFF01 and has a
@@ -47,9 +45,11 @@ const uint8 kReportDescriptorWithIDs[] = {
     0xFF, 0x00, 0x85, 0x01, 0x75, 0x08, 0x95, 0x08, 0x08,
     0x81, 0x02, 0x08, 0x91, 0x02, 0x08, 0xB1, 0x02, 0xC0};
 
-class MockHidConnection : public HidConnection {
+namespace extensions {
+
+class MockHidConnection : public device::HidConnection {
  public:
-  MockHidConnection(scoped_refptr<HidDeviceInfo> device_info)
+  explicit MockHidConnection(scoped_refptr<HidDeviceInfo> device_info)
       : HidConnection(device_info) {}
 
   void PlatformClose() override {}
@@ -117,80 +117,11 @@ class MockHidConnection : public HidConnection {
   ~MockHidConnection() override {}
 };
 
-class MockHidService : public HidService {
- public:
-  MockHidService() : HidService() {
-    // Verify that devices are enumerated properly even when the first
-    // enumeration happens asynchronously.
-    ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE, base::Bind(&MockHidService::LazyFirstEnumeration,
-                              base::Unretained(this)));
-  }
-
-  void Connect(const HidDeviceId& device_id,
-               const ConnectCallback& callback) override {
-    const auto& device_entry = devices().find(device_id);
-    scoped_refptr<HidConnection> connection;
-    if (device_entry != devices().end()) {
-      connection = new MockHidConnection(device_entry->second);
-    }
-
-    ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
-                                            base::Bind(callback, connection));
-  }
-
-  void LazyFirstEnumeration() {
-    AddDevice(kTestDeviceIds[0], 0x18D1, 0x58F0, false);
-    AddDevice(kTestDeviceIds[1], 0x18D1, 0x58F0, true);
-    AddDevice(kTestDeviceIds[2], 0x18D1, 0x58F1, false);
-    FirstEnumerationComplete();
-  }
-
-  void AddDevice(const HidDeviceId& device_id,
-                 int vendor_id,
-                 int product_id,
-                 bool report_id) {
-    std::vector<uint8> report_descriptor;
-    if (report_id) {
-      report_descriptor.insert(
-          report_descriptor.begin(), kReportDescriptorWithIDs,
-          kReportDescriptorWithIDs + sizeof(kReportDescriptorWithIDs));
-    } else {
-      report_descriptor.insert(report_descriptor.begin(), kReportDescriptor,
-                               kReportDescriptor + sizeof(kReportDescriptor));
-    }
-    HidService::AddDevice(new HidDeviceInfo(device_id, vendor_id, product_id,
-                                            "Test Device", "A", kHIDBusTypeUSB,
-                                            report_descriptor));
-  }
-
-  void RemoveDevice(const HidDeviceId& device_id) {
-    HidService::RemoveDevice(device_id);
-  }
-};
-
-class TestDeviceClient : public DeviceClient {
- public:
-  TestDeviceClient() : DeviceClient() {}
-  ~TestDeviceClient() override {}
-
-  MockHidService& mock_service() { return hid_service_; }
-
- private:
-  HidService* GetHidService() override { return &hid_service_; }
-
-  MockHidService hid_service_;
-};
-
-}  // namespace device
-
-namespace extensions {
-
 class TestDevicePermissionsPrompt
     : public DevicePermissionsPrompt,
       public DevicePermissionsPrompt::Prompt::Observer {
  public:
-  TestDevicePermissionsPrompt(content::WebContents* web_contents)
+  explicit TestDevicePermissionsPrompt(content::WebContents* web_contents)
       : DevicePermissionsPrompt(web_contents) {}
 
   ~TestDevicePermissionsPrompt() override { prompt()->SetObserver(nullptr); }
@@ -222,11 +153,57 @@ class HidApiTest : public ShellApiTest {
  public:
   void SetUpOnMainThread() override {
     ShellApiTest::SetUpOnMainThread();
-    device_client_.reset(new device::TestDeviceClient());
+
+    // MockDeviceClient replaces ShellDeviceClient.
+    device_client_.reset(new MockDeviceClient());
+
+    ON_CALL(*device_client_->hid_service(), Connect(_, _))
+        .WillByDefault(Invoke(this, &HidApiTest::Connect));
+    ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE,
+        base::Bind(&HidApiTest::LazyFirstEnumeration, base::Unretained(this)));
+  }
+
+  void Connect(const HidDeviceId& device_id,
+               const device::HidService::ConnectCallback& callback) {
+    const auto& devices = device_client_->hid_service()->devices();
+    const auto& device_entry = devices.find(device_id);
+    scoped_refptr<MockHidConnection> connection;
+    if (device_entry != devices.end()) {
+      connection = new MockHidConnection(device_entry->second);
+    }
+
+    ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
+                                            base::Bind(callback, connection));
+  }
+
+  void LazyFirstEnumeration() {
+    AddDevice(kTestDeviceIds[0], 0x18D1, 0x58F0, false);
+    AddDevice(kTestDeviceIds[1], 0x18D1, 0x58F0, true);
+    AddDevice(kTestDeviceIds[2], 0x18D1, 0x58F1, false);
+    device_client_->hid_service()->FirstEnumerationComplete();
+  }
+
+  void AddDevice(const HidDeviceId& device_id,
+                 int vendor_id,
+                 int product_id,
+                 bool report_id) {
+    std::vector<uint8> report_descriptor;
+    if (report_id) {
+      report_descriptor.insert(
+          report_descriptor.begin(), kReportDescriptorWithIDs,
+          kReportDescriptorWithIDs + sizeof(kReportDescriptorWithIDs));
+    } else {
+      report_descriptor.insert(report_descriptor.begin(), kReportDescriptor,
+                               kReportDescriptor + sizeof(kReportDescriptor));
+    }
+    device_client_->hid_service()->AddDevice(
+        new HidDeviceInfo(device_id, vendor_id, product_id, "Test Device", "A",
+                          device::kHIDBusTypeUSB, report_descriptor));
   }
 
  protected:
-  scoped_ptr<device::TestDeviceClient> device_client_;
+  scoped_ptr<MockDeviceClient> device_client_;
 };
 
 IN_PROC_BROWSER_TEST_F(HidApiTest, HidApp) {
@@ -243,10 +220,8 @@ IN_PROC_BROWSER_TEST_F(HidApiTest, OnDeviceAdded) {
 
   // Add a blocked device first so that the test will fail if a notification is
   // received.
-  device_client_->mock_service().AddDevice(kTestDeviceIds[3], 0x18D1, 0x58F1,
-                                           false);
-  device_client_->mock_service().AddDevice(kTestDeviceIds[4], 0x18D1, 0x58F0,
-                                           false);
+  AddDevice(kTestDeviceIds[3], 0x18D1, 0x58F1, false);
+  AddDevice(kTestDeviceIds[4], 0x18D1, 0x58F0, false);
   ASSERT_TRUE(result_listener.WaitUntilSatisfied());
   EXPECT_EQ("success", result_listener.message());
 }
@@ -261,9 +236,9 @@ IN_PROC_BROWSER_TEST_F(HidApiTest, OnDeviceRemoved) {
 
   // Device C was not returned by chrome.hid.getDevices, the app will not get
   // a notification.
-  device_client_->mock_service().RemoveDevice(kTestDeviceIds[2]);
+  device_client_->hid_service()->RemoveDevice(kTestDeviceIds[2]);
   // Device A was returned, the app will get a notification.
-  device_client_->mock_service().RemoveDevice(kTestDeviceIds[0]);
+  device_client_->hid_service()->RemoveDevice(kTestDeviceIds[0]);
   ASSERT_TRUE(result_listener.WaitUntilSatisfied());
   EXPECT_EQ("success", result_listener.message());
 }
@@ -276,12 +251,11 @@ IN_PROC_BROWSER_TEST_F(HidApiTest, GetUserSelectedDevices) {
   ASSERT_TRUE(open_listener.WaitUntilSatisfied());
 
   ExtensionTestMessageListener remove_listener("removed", false);
-  device_client_->mock_service().RemoveDevice(kTestDeviceIds[0]);
+  device_client_->hid_service()->RemoveDevice(kTestDeviceIds[0]);
   ASSERT_TRUE(remove_listener.WaitUntilSatisfied());
 
   ExtensionTestMessageListener add_listener("added", false);
-  device_client_->mock_service().AddDevice(kTestDeviceIds[0], 0x18D1, 0x58F0,
-                                           true);
+  AddDevice(kTestDeviceIds[0], 0x18D1, 0x58F0, true);
   ASSERT_TRUE(add_listener.WaitUntilSatisfied());
 }
 
diff --git a/extensions/browser/api/usb/usb_apitest.cc b/extensions/browser/api/usb/usb_apitest.cc
index 7b654c7..4257630 100644
--- a/extensions/browser/api/usb/usb_apitest.cc
+++ b/extensions/browser/api/usb/usb_apitest.cc
@@ -5,7 +5,7 @@
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/test/test_utils.h"
-#include "device/core/device_client.h"
+#include "device/core/mock_device_client.h"
 #include "device/usb/mock_usb_device.h"
 #include "device/usb/mock_usb_device_handle.h"
 #include "device/usb/mock_usb_service.h"
@@ -20,17 +20,13 @@ using testing::_;
 using testing::AnyNumber;
 using testing::Invoke;
 using testing::Return;
-using content::BrowserThread;
-using device::DeviceClient;
+using device::MockDeviceClient;
 using device::MockUsbDevice;
 using device::MockUsbDeviceHandle;
-using device::MockUsbService;
 using device::UsbConfigDescriptor;
-using device::UsbDevice;
 using device::UsbDeviceHandle;
 using device::UsbEndpointDirection;
 using device::UsbInterfaceDescriptor;
-using device::UsbService;
 
 namespace extensions {
 
@@ -54,7 +50,7 @@ class TestDevicePermissionsPrompt
     : public DevicePermissionsPrompt,
       public DevicePermissionsPrompt::Prompt::Observer {
  public:
-  TestDevicePermissionsPrompt(content::WebContents* web_contents)
+  explicit TestDevicePermissionsPrompt(content::WebContents* web_contents)
       : DevicePermissionsPrompt(web_contents) {}
 
   void ShowDialog() override { prompt()->SetObserver(this); }
@@ -70,19 +66,6 @@ class TestDevicePermissionsPrompt
   }
 };
 
-class TestDeviceClient : public DeviceClient {
- public:
-  TestDeviceClient() : DeviceClient() {}
-  ~TestDeviceClient() override {}
-
-  MockUsbService& mock_usb_service() { return usb_service_; }
-
- private:
-  UsbService* GetUsbService() override { return &usb_service_; }
-
-  MockUsbService usb_service_;
-};
-
 class TestExtensionsAPIClient : public ShellExtensionsAPIClient {
  public:
   TestExtensionsAPIClient() : ShellExtensionsAPIClient() {}
@@ -98,6 +81,9 @@ class UsbApiTest : public ShellApiTest {
   void SetUpOnMainThread() override {
     ShellApiTest::SetUpOnMainThread();
 
+    // MockDeviceClient replaces ShellDeviceClient.
+    device_client_.reset(new MockDeviceClient());
+
     std::vector<UsbConfigDescriptor> configs;
     UsbConfigDescriptor config;
     config.configuration_value = 1;
@@ -110,14 +96,13 @@ class UsbApiTest : public ShellApiTest {
     mock_device_handle_ = new MockUsbDeviceHandle(mock_device_.get());
     EXPECT_CALL(*mock_device_.get(), Open(_))
         .WillRepeatedly(InvokeCallback<0>(mock_device_handle_));
-    device_client_.reset(new TestDeviceClient());
-    device_client_->mock_usb_service().AddDevice(mock_device_);
+    device_client_->usb_service()->AddDevice(mock_device_);
   }
 
  protected:
   scoped_refptr<MockUsbDeviceHandle> mock_device_handle_;
   scoped_refptr<MockUsbDevice> mock_device_;
-  scoped_ptr<TestDeviceClient> device_client_;
+  scoped_ptr<MockDeviceClient> device_client_;
 };
 
 }  // namespace
@@ -221,10 +206,10 @@ IN_PROC_BROWSER_TEST_F(UsbApiTest, OnDeviceAdded) {
   ASSERT_TRUE(load_listener.WaitUntilSatisfied());
 
   scoped_refptr<MockUsbDevice> device(new MockUsbDevice(0x18D1, 0x58F0));
-  device_client_->mock_usb_service().AddDevice(device);
+  device_client_->usb_service()->AddDevice(device);
 
   device = new MockUsbDevice(0x18D1, 0x58F1);
-  device_client_->mock_usb_service().AddDevice(device);
+  device_client_->usb_service()->AddDevice(device);
 
   ASSERT_TRUE(result_listener.WaitUntilSatisfied());
 }
@@ -237,7 +222,7 @@ IN_PROC_BROWSER_TEST_F(UsbApiTest, OnDeviceRemoved) {
   ASSERT_TRUE(LoadApp("api_test/usb/remove_event"));
   ASSERT_TRUE(load_listener.WaitUntilSatisfied());
 
-  device_client_->mock_usb_service().RemoveDevice(mock_device_);
+  device_client_->usb_service()->RemoveDevice(mock_device_);
   ASSERT_TRUE(result_listener.WaitUntilSatisfied());
 }
 
@@ -252,7 +237,7 @@ IN_PROC_BROWSER_TEST_F(UsbApiTest, GetUserSelectedDevices) {
   ASSERT_TRUE(LoadApp("api_test/usb/get_user_selected_devices"));
   ASSERT_TRUE(ready_listener.WaitUntilSatisfied());
 
-  device_client_->mock_usb_service().RemoveDevice(mock_device_);
+  device_client_->usb_service()->RemoveDevice(mock_device_);
   ASSERT_TRUE(result_listener.WaitUntilSatisfied());
 }
 
diff --git a/extensions/extensions_tests.gyp b/extensions/extensions_tests.gyp
index ee619eb..771d231 100644
--- a/extensions/extensions_tests.gyp
+++ b/extensions/extensions_tests.gyp
@@ -85,6 +85,8 @@
         '<(DEPTH)/content/content_shell_and_tests.gyp:content_browser_test_support',
         '<(DEPTH)/content/content_shell_and_tests.gyp:test_support_content',
         '<(DEPTH)/device/bluetooth/bluetooth.gyp:device_bluetooth_mocks',
+        '<(DEPTH)/device/core/core.gyp:device_core_mocks',
+        '<(DEPTH)/device/hid/hid.gyp:device_hid_mocks',
         '<(DEPTH)/device/usb/usb.gyp:device_usb_mocks',
         '<(DEPTH)/testing/gmock.gyp:gmock',
         '<(DEPTH)/testing/gtest.gyp:gtest',