Bluetooth: gather usage metrics

chrome/browser/metrics/metrics_log.h

Index: chrome/browser/metrics/metrics_log.h
diff --git a/chrome/browser/metrics/metrics_log.h b/chrome/browser/metrics/metrics_log.h
index f5cf34e9235085c1440661515c4a7956dd14f613..7cec98484c829181a382716ae517f948e780f303 100644
--- a/chrome/browser/metrics/metrics_log.h
+++ b/chrome/browser/metrics/metrics_log.h
@@ -30,6 +30,10 @@ namespace base {
 class DictionaryValue;
 }
 
+namespace device {
+class BluetoothAdapter;
+}
+
 namespace tracked_objects {
 struct ProcessDataSnapshot;
 }
@@ -189,6 +193,11 @@ class MetricsLog : public MetricsLogBase {
   // This is a no-op if called on a non-Windows platform.
   void WriteGoogleUpdateProto(const GoogleUpdateMetrics& google_update_metrics);
 
+  // Writes info about paired Bluetooth devices on this system.
+  // This is a no-op if called on a non-Chrome OS platform.
+  void WriteBluetoothProto(metrics::SystemProfileProto::Hardware* hardware,
+                           scoped_refptr<device::BluetoothAdapter> adapter);
+
   // Observes network state to provide values for SystemProfile::Network.
   MetricsNetworkObserver network_observer_;
 
@@ -196,6 +205,12 @@ class MetricsLog : public MetricsLogBase {
   metrics::PerfProvider perf_provider_;
 #endif
 
+  // Weak pointer factory for generating 'this' pointers that might live longer
+  // than we do.
+  // Note: This should remain the last member so it'll be destroyed and
+  // invalidate its weak pointers before any other members are destroyed.

[Ilya Sherman, 2013/04/23 00:09:43]

Hmm, why is the destruction order important?  Is there some particular other
member that relies on this destruction order?

[keybuk, 2013/04/23 00:41:42]

comment copied from other code ;) removed

+  base::WeakPtrFactory<MetricsLog> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(MetricsLog);
 };