Delayed adding BluetoothEventRouter as BluetoothAdapter observer until when the

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..b969e8b46eadd12fe0bfdd4433a25f6993ce7562 100644
--- a/chrome/browser/extensions/bluetooth_event_router.cc
+++ b/chrome/browser/extensions/bluetooth_event_router.cc
@@ -27,10 +27,20 @@ ExtensionBluetoothEventRouter::ExtensionBluetoothEventRouter(Profile* profile)
       responsible_for_discovery_(false),
       profile_(profile),
       adapter_(device::BluetoothAdapterFactory::DefaultAdapter()),
+      observing_(false),
+      next_socket_id_(1) {
+  DCHECK(profile_);
+}
+
+ExtensionBluetoothEventRouter::ExtensionBluetoothEventRouter(
+    Profile* profile, device::BluetoothAdapter* adapter)
+    : send_discovery_events_(false),
+      responsible_for_discovery_(false),
+      profile_(profile),
+      adapter_(adapter),
+      observing_(false),
       next_socket_id_(1) {
   DCHECK(profile_);
-  if (adapter_.get())
-    adapter_->AddObserver(this);
 }
 
 ExtensionBluetoothEventRouter::~ExtensionBluetoothEventRouter() {
@@ -62,6 +72,22 @@ bool ExtensionBluetoothEventRouter::ReleaseSocket(int id) {
   return true;
 }
 
+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;
+}
+
+void ExtensionBluetoothEventRouter::OnEventListenerAdded(
+    const std::string& event_name) {
+  if (!observing_ && IsBluetoothEvent(event_name) && adapter_.get()) {
+    adapter_->AddObserver(this);
+    observing_ = true;
+  }
+}
+
 scoped_refptr<device::BluetoothSocket>
 ExtensionBluetoothEventRouter::GetSocket(int id) {
   SocketMap::iterator socket_entry = socket_map_.find(id);