Fix assigning NULL to scoped_refptr

Update code where NULL or 0 is assigned to a scoped_refptr to reset it. Just
call reset() instead. If operator=(std::nullptr_t) is added these assignments
become ambiguous.

This CL was uploaded by git cl split.

R=odejesush@chromium.org

Bug: 1024981
Change-Id: I24b8ae005c530c473b32745f398319db3fe39dcf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1918320
Auto-Submit: kylechar <kylechar@chromium.org>
Reviewed-by: Ovidio de Jesús Ruiz-Henríquez <odejesush@chromium.org>
Commit-Queue: kylechar <kylechar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715687}

device/bluetooth/bluetooth_socket_net.cc

@@ -135,7 +135,7 @@ void BluetoothSocketNet::DoClose() {
   // Note: Closing |tcp_socket_| above released all potential pending
   // Send/Receive operations, so we can no safely release the state associated
   // to those pending operations.
-  read_buffer_ = NULL;
+  read_buffer_.reset();
   base::queue<std::unique_ptr<WriteRequest>> empty;
   std::swap(write_queue_, empty);
 

device/bluetooth/bluetooth_socket_thread.cc

@@ -25,7 +25,7 @@ scoped_refptr<BluetoothSocketThread> BluetoothSocketThread::Get() {
 // static
 void BluetoothSocketThread::CleanupForTesting() {
   DCHECK(g_instance.Get().get());
-  g_instance.Get() = NULL;
+  g_instance.Get().reset();
 }
 
 BluetoothSocketThread::BluetoothSocketThread()
@@ -35,7 +35,7 @@ BluetoothSocketThread::~BluetoothSocketThread() {
   if (thread_) {
     thread_->Stop();
     thread_.reset(NULL);
-    task_runner_ = NULL;
+    task_runner_.reset();
   }
 }
 

device/bluetooth/bluez/bluetooth_gatt_bluez_unittest.cc

@@ -139,7 +139,7 @@ class BluetoothGattBlueZTest : public testing::Test {
   }
 
   void TearDown() override {
-    adapter_ = NULL;
+    adapter_.reset();
     update_sessions_.clear();
     gatt_conn_.reset();
     bluez::BluezDBusManager::Shutdown();
@@ -589,7 +589,7 @@ TEST_F(BluetoothGattBlueZTest, GattServiceAddedAndRemoved) {
 TEST_F(BluetoothGattBlueZTest, ServicesDiscoveredBeforeAdapterIsCreated) {
   // Tests that all GATT objects are created for a device whose D-Bus objects
   // were already exposed and for which services have been resolved.
-  adapter_ = NULL;
+  adapter_.reset();
   ASSERT_FALSE(device::BluetoothAdapterFactory::HasSharedInstanceForTesting());
 
   // Create the fake D-Bus objects.
@@ -685,7 +685,7 @@ TEST_F(BluetoothGattBlueZTest, DiscoverCachedServices) {
   // This unit test tests that all remote GATT objects are created for D-Bus
   // objects that were already exposed and all relevant events have been
   // dispatched.
-  adapter_ = NULL;
+  adapter_.reset();
   ASSERT_FALSE(device::BluetoothAdapterFactory::HasSharedInstanceForTesting());
 
   // Create the fake D-Bus objects.
@@ -774,7 +774,7 @@ TEST_F(BluetoothGattBlueZTest, DiscoverNewServices) {
 TEST_F(BluetoothGattBlueZTest, DiscoverCachedAndNewServices) {
   // This unit test tests that all remote GATT objects are created for D-Bus
   // objects that were already exposed and for new GATT Objects.
-  adapter_ = NULL;
+  adapter_.reset();
   ASSERT_FALSE(device::BluetoothAdapterFactory::HasSharedInstanceForTesting());
 
   // Create the fake D-Bus objects.