Lazy-creates BluetoothAdapter in ExtensionBluetoothEventRouter (EBEE).

chrome/browser/extensions/bluetooth_event_router.cc

Index: chrome/browser/extensions/bluetooth_event_router.cc
diff --git a/chrome/browser/extensions/bluetooth_event_router.cc b/chrome/browser/extensions/bluetooth_event_router.cc
index d38db9e8b925a6438b7a199889ee2f576b1ea5dc..44e6f8742757a3c75190bd60b50e2e707e57eaf9 100644
--- a/chrome/browser/extensions/bluetooth_event_router.cc
+++ b/chrome/browser/extensions/bluetooth_event_router.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/extensions/bluetooth_event_router.h"
 
 #include <map>
+#include <string>
 
 #include "base/json/json_writer.h"
 #include "base/memory/ref_counted.h"
@@ -26,20 +27,45 @@ ExtensionBluetoothEventRouter::ExtensionBluetoothEventRouter(Profile* profile)
     : send_discovery_events_(false),
       responsible_for_discovery_(false),
       profile_(profile),
-      adapter_(device::BluetoothAdapterFactory::DefaultAdapter()),
+      adapter_(NULL),
+      num_event_listeners_(0),
       next_socket_id_(1) {
   DCHECK(profile_);
-  if (adapter_.get())
-    adapter_->AddObserver(this);
 }
 
 ExtensionBluetoothEventRouter::~ExtensionBluetoothEventRouter() {
-  if (adapter_.get())
-    adapter_->RemoveObserver(this);
+  MaybeReleaseAdapter();
 
   socket_map_.clear();
 }
 
+scoped_refptr<const device::BluetoothAdapter>
+ExtensionBluetoothEventRouter::adapter() {
+  return GetMutableAdapter();
+}
+
+scoped_refptr<device::BluetoothAdapter>
+ExtensionBluetoothEventRouter::GetMutableAdapter() {
+  if (adapter_)
+    return adapter_;
+
+  return device::BluetoothAdapterFactory::DefaultAdapter();
+}
+
+void ExtensionBluetoothEventRouter::InitializeAdapterIfNeeded() {
+  if (!adapter_) {
+    adapter_ = GetMutableAdapter();
+    adapter_->AddObserver(this);
+  }
+}
+
+void ExtensionBluetoothEventRouter::MaybeReleaseAdapter() {
+  if (adapter_) {
+    adapter_->RemoveObserver(this);
+    adapter_ = NULL;
+  }
+}
+
 int ExtensionBluetoothEventRouter::RegisterSocket(
     scoped_refptr<device::BluetoothSocket> socket) {
   // If there is a socket registered with the same fd, just return it's id
@@ -51,6 +77,8 @@ int ExtensionBluetoothEventRouter::RegisterSocket(
   }
   int return_id = next_socket_id_++;
   socket_map_[return_id] = socket;
+  InitializeAdapterIfNeeded();
+
   return return_id;
 }
 
@@ -59,6 +87,9 @@ bool ExtensionBluetoothEventRouter::ReleaseSocket(int id) {
   if (socket_entry == socket_map_.end())
     return false;
   socket_map_.erase(socket_entry);
+  if (!IsAdapterNeeded())
+    MaybeReleaseAdapter();
+
   return true;
 }
 
@@ -70,6 +101,37 @@ ExtensionBluetoothEventRouter::GetSocket(int id) {
   return socket_entry->second;
 }
 
+// static
+bool ExtensionBluetoothEventRouter::IsBluetoothEvent(
+    const std::string& event_name) {
+  return
+      event_name == extensions::event_names::kBluetoothOnAvailabilityChanged ||
+      event_name == extensions::event_names::kBluetoothOnDiscoveringChanged ||
+      event_name == extensions::event_names::kBluetoothOnPowerChanged;
+}
+
+bool ExtensionBluetoothEventRouter::IsAdapterNeeded() const {
+  return num_event_listeners_ > 0 || socket_map_.size() > 0;
+}
+
+void ExtensionBluetoothEventRouter::OnEventListenerAdded(
+    const std::string& event_name) {
+  if (IsBluetoothEvent(event_name)) {
+    num_event_listeners_++;
+    InitializeAdapterIfNeeded();
+  }
+}
+
+void ExtensionBluetoothEventRouter::OnEventListenerRemoved(
+    const std::string& event_name) {
+  if (IsBluetoothEvent(event_name)) {
+    num_event_listeners_--;
+    DCHECK(num_event_listeners_ >= 0);
+    if (!IsAdapterNeeded())
+      MaybeReleaseAdapter();
+  }
+}
+
 void ExtensionBluetoothEventRouter::SetResponsibleForDiscovery(
     bool responsible) {
   responsible_for_discovery_ = responsible;
@@ -103,7 +165,7 @@ void ExtensionBluetoothEventRouter::DispatchDeviceEvent(
 
 void ExtensionBluetoothEventRouter::AdapterPresentChanged(
     device::BluetoothAdapter* adapter, bool present) {
-  if (adapter != adapter_.get()) {
+  if (adapter != adapter_) {
     DVLOG(1) << "Ignoring event for adapter " << adapter->address();
     return;
   }
@@ -115,7 +177,7 @@ void ExtensionBluetoothEventRouter::AdapterPresentChanged(
 
 void ExtensionBluetoothEventRouter::AdapterPoweredChanged(
     device::BluetoothAdapter* adapter, bool has_power) {
-  if (adapter != adapter_.get()) {
+  if (adapter != adapter_) {
     DVLOG(1) << "Ignoring event for adapter " << adapter->address();
     return;
   }
@@ -127,7 +189,7 @@ void ExtensionBluetoothEventRouter::AdapterPoweredChanged(
 
 void ExtensionBluetoothEventRouter::AdapterDiscoveringChanged(
     device::BluetoothAdapter* adapter, bool discovering) {
-  if (adapter != adapter_.get()) {
+  if (adapter != adapter_) {
     DVLOG(1) << "Ignoring event for adapter " << adapter->address();
     return;
   }
@@ -146,7 +208,7 @@ void ExtensionBluetoothEventRouter::AdapterDiscoveringChanged(
 void ExtensionBluetoothEventRouter::DeviceAdded(
     device::BluetoothAdapter* adapter,
     device::BluetoothDevice* device) {
-  if (adapter != adapter_.get()) {
+  if (adapter != adapter_) {
     DVLOG(1) << "Ignoring event for adapter " << adapter->address();
     return;
   }