Allow Device Service access from any thread

This allows multiple device.mojom.DeviceService connections to the
Device Service and changes content::GetDeviceService() to safely
maintain independent sequence-local connections.

The new behavior corrects an issue where an inadvertent background-
thread client could trample the global Device Service instance early
in startup, leaving all main-thread clients with a permanently broken
connection.

Bug: 1041804
Change-Id: I3efcb661c9508e1e0007d00f2f9f963c26220de4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2168829Reviewed-by: Reilly Grant <reillyg@chromium.org>
Commit-Queue: Ken Rockot <rockot@google.com>
Cr-Commit-Position: refs/heads/master@{#763452}

content/browser/device/device_service.cc

@@ -94,9 +94,10 @@ void BindDeviceServiceReceiver(
       service_slot;
   auto& service = service_slot->GetOrCreateValue();
 
-  // This function should only be called once during the lifetime of the
-  // service's bound sequence.
-  DCHECK(!service);
+  if (service) {
+    service->AddReceiver(std::move(receiver));
+    return;
+  }
 
 #if defined(OS_ANDROID)
   JNIEnv* env = base::android::AttachCurrentThread();

services/device/device_service.cc

@@ -99,8 +99,7 @@ DeviceService::DeviceService(
     const WakeLockContextCallback& wake_lock_context_callback,
     const base::android::JavaRef<jobject>& java_nfc_delegate,
     mojo::PendingReceiver<mojom::DeviceService> receiver)
-    : receiver_(this, std::move(receiver)),
-      file_task_runner_(std::move(file_task_runner)),
+    : file_task_runner_(std::move(file_task_runner)),
       io_task_runner_(std::move(io_task_runner)),
       url_loader_factory_(std::move(url_loader_factory)),
       network_connection_tracker_(network_connection_tracker),
@@ -108,6 +107,7 @@ DeviceService::DeviceService(
       wake_lock_context_callback_(wake_lock_context_callback),
       wake_lock_provider_(file_task_runner_, wake_lock_context_callback_),
       java_interface_provider_initialized_(false) {
+  receivers_.Add(this, std::move(receiver));
   java_nfc_delegate_.Reset(java_nfc_delegate);
 }
 #else
@@ -118,13 +118,13 @@ DeviceService::DeviceService(
     network::NetworkConnectionTracker* network_connection_tracker,
     const std::string& geolocation_api_key,
     mojo::PendingReceiver<mojom::DeviceService> receiver)
-    : receiver_(this, std::move(receiver)),
-      file_task_runner_(std::move(file_task_runner)),
+    : file_task_runner_(std::move(file_task_runner)),
       io_task_runner_(std::move(io_task_runner)),
       url_loader_factory_(std::move(url_loader_factory)),
       network_connection_tracker_(network_connection_tracker),
       geolocation_api_key_(geolocation_api_key),
       wake_lock_provider_(file_task_runner_, wake_lock_context_callback_) {
+  receivers_.Add(this, std::move(receiver));
 #if (defined(OS_LINUX) && defined(USE_UDEV)) || defined(OS_WIN) || \
     defined(OS_MACOSX)
   serial_port_manager_ = std::make_unique<SerialPortManagerImpl>(
@@ -162,6 +162,11 @@ DeviceService::~DeviceService() {
 #endif
 }
 
+void DeviceService::AddReceiver(
+    mojo::PendingReceiver<mojom::DeviceService> receiver) {
+  receivers_.Add(this, std::move(receiver));
+}
+
 void DeviceService::SetPlatformSensorProviderForTesting(
     std::unique_ptr<PlatformSensorProvider> provider) {
   DCHECK(!sensor_provider_);

services/device/device_service.h

@@ -12,7 +12,7 @@
 #include "base/memory/ref_counted.h"
 #include "build/build_config.h"
 #include "mojo/public/cpp/bindings/pending_receiver.h"
-#include "mojo/public/cpp/bindings/receiver.h"
+#include "mojo/public/cpp/bindings/receiver_set.h"
 #include "services/device/geolocation/geolocation_provider.h"
 #include "services/device/geolocation/geolocation_provider_impl.h"
 #include "services/device/geolocation/public_ip_address_geolocation_provider.h"
@@ -126,6 +126,8 @@ class DeviceService : public mojom::DeviceService {
 #endif
   ~DeviceService() override;
 
+  void AddReceiver(mojo::PendingReceiver<mojom::DeviceService> receiver);
+
   void SetPlatformSensorProviderForTesting(
       std::unique_ptr<PlatformSensorProvider> provider);
 
@@ -199,7 +201,7 @@ class DeviceService : public mojom::DeviceService {
   void BindUsbDeviceManagerTest(
       mojo::PendingReceiver<mojom::UsbDeviceManagerTest> receiver) override;
 
-  mojo::Receiver<mojom::DeviceService> receiver_;
+  mojo::ReceiverSet<mojom::DeviceService> receivers_;
   std::unique_ptr<PowerMonitorMessageBroadcaster>
       power_monitor_message_broadcaster_;
   std::unique_ptr<PublicIpAddressGeolocationProvider>