Run clang-tidy modernize-use-equals-{delete,default} on //dbus

See the bugs and cxx post for justification and details:
https://groups.google.com/a/chromium.org/forum/#!topic/cxx/RkOHzIK6Tq8

This change was done using clang-tidy as described here:
https://chromium.googlesource.com/chromium/src/+/lkcr/docs/clang_tidy.md

In some cases the the tool leaves behind a string of commas where it
replaced a member initializer list
(https://bugs.llvm.org/show_bug.cgi?id=35051). They were cleaned up with:
  git diff --name-only | \
    xargs sed -E -i 's/(^\s*|\)\s*):[ ,]*= default/\1 = default/'

BUG=778959,778957

Change-Id: I3435f847095ac0fbe5532f7859a67acdb4b23e8c
Reviewed-on: https://chromium-review.googlesource.com/789741
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Commit-Queue: Chris Watkins <watk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520038}

dbus/bus.cc

@@ -151,8 +151,7 @@ Bus::Options::Options()
     connection_type(PRIVATE) {
 }
 
-Bus::Options::~Options() {
-}
+Bus::Options::~Options() = default;
 
 Bus::Bus(const Options& options)
     : bus_type_(options.bus_type),

dbus/bus_unittest.cc

@@ -30,7 +30,7 @@ namespace {
 class RunLoopWithExpectedCount {
  public:
   RunLoopWithExpectedCount() : expected_quit_calls_(0), actual_quit_calls_(0) {}
-  ~RunLoopWithExpectedCount() {}
+  ~RunLoopWithExpectedCount() = default;
 
   void Run(int expected_quit_calls) {
     DCHECK_EQ(0, expected_quit_calls_);

dbus/dbus_statistics_unittest.cc

@@ -12,8 +12,7 @@ namespace dbus {
 
 class DBusStatisticsTest : public testing::Test {
  public:
-  DBusStatisticsTest() {
-  }
+  DBusStatisticsTest() = default;
 
   void SetUp() override { statistics::Initialize(); }
 

dbus/end_to_end_async_unittest.cc

@@ -589,8 +589,7 @@ TEST_F(EndToEndAsyncTest, TestHugeSignal) {
 
 class SignalMultipleHandlerTest : public EndToEndAsyncTest {
  public:
-  SignalMultipleHandlerTest() {
-  }
+  SignalMultipleHandlerTest() = default;
 
   void SetUp() override {
     // Set up base class.

dbus/end_to_end_sync_unittest.cc

@@ -19,8 +19,7 @@ namespace dbus {
 // operations (i.e. ExportedObject side).
 class EndToEndSyncTest : public testing::Test {
  public:
-  EndToEndSyncTest() {
-  }
+  EndToEndSyncTest() = default;
 
   void SetUp() override {
     // Start the test service;

dbus/message.cc

@@ -446,8 +446,7 @@ MessageWriter::MessageWriter(Message* message)
     dbus_message_iter_init_append(message_->raw_message(), &raw_message_iter_);
 }
 
-MessageWriter::~MessageWriter() {
-}
+MessageWriter::~MessageWriter() = default;
 
 void MessageWriter::AppendByte(uint8_t value) {
   AppendBasic(DBUS_TYPE_BYTE, &value);
@@ -716,9 +715,7 @@ MessageReader::MessageReader(Message* message)
     dbus_message_iter_init(message_->raw_message(), &raw_message_iter_);
 }
 
-
-MessageReader::~MessageReader() {
-}
+MessageReader::~MessageReader() = default;
 
 bool MessageReader::HasMoreData() {
   const int dbus_type = dbus_message_iter_get_arg_type(&raw_message_iter_);

dbus/mock_bus.cc

@@ -11,7 +11,6 @@ namespace dbus {
 MockBus::MockBus(const Bus::Options& options) : Bus(options) {
 }
 
-MockBus::~MockBus() {
-}
+MockBus::~MockBus() = default;
 
 }  // namespace dbus

dbus/mock_exported_object.cc

@@ -11,7 +11,6 @@ MockExportedObject::MockExportedObject(Bus* bus,
     : ExportedObject(bus, object_path) {
 }
 
-MockExportedObject::~MockExportedObject() {
-}
+MockExportedObject::~MockExportedObject() = default;
 
 }  // namespace dbus

dbus/mock_object_manager.cc

@@ -12,7 +12,6 @@ MockObjectManager::MockObjectManager(Bus* bus,
     : ObjectManager(bus, service_name, object_path) {
 }
 
-MockObjectManager::~MockObjectManager() {
-}
+MockObjectManager::~MockObjectManager() = default;
 
 }  // namespace dbus

dbus/mock_object_proxy.cc

@@ -12,8 +12,7 @@ MockObjectProxy::MockObjectProxy(Bus* bus,
     : ObjectProxy(bus, service_name, object_path, DEFAULT_OPTIONS) {
 }
 
-MockObjectProxy::~MockObjectProxy() {
-}
+MockObjectProxy::~MockObjectProxy() = default;
 
 void MockObjectProxy::CallMethod(MethodCall* method_call,
                                  int timeout_ms,

dbus/mock_unittest.cc

@@ -28,8 +28,7 @@ namespace dbus {
 
 class MockTest : public testing::Test {
  public:
-  MockTest() {
-  }
+  MockTest() = default;
 
   void SetUp() override {
     // Create a mock bus.

dbus/object_manager.cc

@@ -26,8 +26,7 @@ ObjectManager::Object::Object()
   : object_proxy(nullptr) {
 }
 
-ObjectManager::Object::~Object() {
-}
+ObjectManager::Object::~Object() = default;
 
 ObjectManager::ObjectManager(Bus* bus,
                              const std::string& service_name,

dbus/property.cc

@@ -23,7 +23,7 @@ namespace dbus {
 
 PropertyBase::PropertyBase() : property_set_(nullptr), is_valid_(false) {}
 
-PropertyBase::~PropertyBase() {}
+PropertyBase::~PropertyBase() = default;
 
 void PropertyBase::Init(PropertySet* property_set, const std::string& name) {
   DCHECK(!property_set_);
@@ -45,8 +45,7 @@ PropertySet::PropertySet(
       property_changed_callback_(property_changed_callback),
       weak_ptr_factory_(this) {}
 
-PropertySet::~PropertySet() {
-}
+PropertySet::~PropertySet() = default;
 
 void PropertySet::RegisterProperty(const std::string& name,
                                    PropertyBase* property) {

dbus/property_unittest.cc

@@ -31,7 +31,7 @@ namespace dbus {
 // Property<>.
 class PropertyTest : public testing::Test {
  public:
-  PropertyTest() {}
+  PropertyTest() = default;
 
   struct Properties : public PropertySet {
     Property<std::string> name;

dbus/test_service.cc

@@ -40,8 +40,7 @@ TestService::Options::Options()
     : request_ownership_options(Bus::REQUIRE_PRIMARY) {
 }
 
-TestService::Options::~Options() {
-}
+TestService::Options::~Options() = default;
 
 TestService::TestService(const Options& options)
     : base::Thread("TestService"),