Implement BluetoothDeviceBlueZ::GetServiceRecords.

device/bluetooth/bluez/bluetooth_service_record_bluez.cc

Index: device/bluetooth/bluez/bluetooth_service_record_bluez.cc
diff --git a/device/bluetooth/bluez/bluetooth_service_record_bluez.cc b/device/bluetooth/bluez/bluetooth_service_record_bluez.cc
index 5a3178f2616d169524f084900ccbf6120becb4ae..262e4e1c3254c2305397df6c91e110adee555ab2 100644
--- a/device/bluetooth/bluez/bluetooth_service_record_bluez.cc
+++ b/device/bluetooth/bluez/bluetooth_service_record_bluez.cc
@@ -4,13 +4,13 @@
 
 #include "device/bluetooth/bluez/bluetooth_service_record_bluez.h"
 
+#include <utility>
+
 #include "base/values.h"
 
 namespace bluez {
 
-BluetoothServiceRecordBlueZ::BluetoothServiceRecordBlueZ(
-    const std::map<uint16_t, BluetoothServiceAttributeValueBlueZ>& attributes)
-    : attributes_(attributes) {}
+BluetoothServiceRecordBlueZ::BluetoothServiceRecordBlueZ() {}
 
 BluetoothServiceRecordBlueZ::BluetoothServiceRecordBlueZ(
     const BluetoothServiceRecordBlueZ& record) {
@@ -35,4 +35,14 @@ BluetoothServiceRecordBlueZ::GetAttributeValue(uint16_t attribute_id) const {
   return it->second;
 }
 
+void BluetoothServiceRecordBlueZ::AddRecordEntry(
+    uint16_t id,
+    const BluetoothServiceAttributeValueBlueZ& value) {
+  auto it = attributes_.find(id);
+  if (it != attributes_.end())
+    attributes_.erase(it);

[xiyuan, 2016/06/29 22:43:08]

Why do we need to explicitly remove the existing one? Why not just

  attributes_[id] = value;

[rkc, 2016/06/30 20:02:24]

This is a painful part of std::map. This apparently always first creates a
BluetoothServiceAttributeValueBlueZ() first, and then tries to copy over it.
Since we don't have (nor want) a constructor for
BluetoothServiceAttributeValueBlueZ(), the only way around this is to use
insert.

Using insert has the side-effect of requiring us to explicitly erase first.

[xiyuan, 2016/06/30 20:07:34]

Acknowledged.

+  attributes_.insert(

[xiyuan, 2016/06/30 20:07:34]

nit: could this be

  attributes_.emplace(id, value);

?

[rkc, 2016/06/30 20:15:54]

For some reason, map::emplace breaks some bots, while vector::emplace_back
doesn't.
https://luci-logdog.appspot.com/v/?s=chromium%2Fbb%2Ftryserver.chromium.linux...

+      std::pair<uint16_t, BluetoothServiceAttributeValueBlueZ>(id, value));
+}
+
 }  // namespace bluez