components/arc: implement multi advertising

components/arc/bluetooth/arc_bluetooth_bridge.h

Index: components/arc/bluetooth/arc_bluetooth_bridge.h
diff --git a/components/arc/bluetooth/arc_bluetooth_bridge.h b/components/arc/bluetooth/arc_bluetooth_bridge.h
index 6a484b186eeadcade42ca5649f4ef0492579475b..229922ce3b2c8d94052fc65dbaac5a7bb326ff82 100644
--- a/components/arc/bluetooth/arc_bluetooth_bridge.h
+++ b/components/arc/bluetooth/arc_bluetooth_bridge.h
@@ -21,6 +21,7 @@
 #include "components/arc/instance_holder.h"
 #include "device/bluetooth/bluetooth_adapter.h"
 #include "device/bluetooth/bluetooth_adapter_factory.h"
+#include "device/bluetooth/bluetooth_advertisement.h"
 #include "device/bluetooth/bluetooth_device.h"
 #include "device/bluetooth/bluetooth_discovery_session.h"
 #include "device/bluetooth/bluetooth_local_gatt_service.h"
@@ -276,6 +277,17 @@ class ArcBluetoothBridge
   void RemoveSdpRecord(uint32_t service_handle,
                        const RemoveSdpRecordCallback& callback) override;
 
+  // Set up or disable multiple advertising.
+  void ReserveAdvertisementHandle(
+      const ReserveAdvertisementHandleCallback& callback) override;
+  void BroadcastAdvertisement(
+      int32_t adv_handle,
+      std::unique_ptr<device::BluetoothAdvertisement::Data> advertisement,
+      const BroadcastAdvertisementCallback& callback) override;
+  void ReleaseAdvertisementHandle(
+      int32_t adv_handle,
+      const ReleaseAdvertisementHandleCallback& callback) override;
+
   // Chrome observer callbacks
   void OnPoweredOn(
       const base::Callback<void(mojom::BluetoothAdapterState)>& callback) const;
@@ -382,6 +394,42 @@ class ArcBluetoothBridge
       const device::BluetoothUUID& target_uuid,
       bluez::BluetoothServiceRecordBlueZ::ErrorCode error_code);
 
+  // Callbacks for managing advertisements registered from the instance.
+
+  // Called when we have an open slot in the advertisement map and want to
+  // register the advertisement given by |data| for handle |adv_handle|.
+  void OnReadyToRegisterAdvertisement(

[Rahul Chaturvedi, 2016/09/16 22:37:22]

Tests for these methods?

+      const BroadcastAdvertisementCallback& callback,
+      int32_t adv_handle,
+      std::unique_ptr<device::BluetoothAdvertisement::Data> data);
+  // Called when we've successfully registered a new advertisement for
+  // handle |adv_handle|.
+  void OnRegisterAdvertisementDone(
+      const BroadcastAdvertisementCallback& callback,
+      int32_t adv_handle,
+      scoped_refptr<device::BluetoothAdvertisement> advertisement);
+  // Called when the attempt to register an advertisement for handle
+  // |adv_handle| has failed. |adv_handle| remains reserved, but no
+  // advertisement is associated with it.
+  void OnRegisterAdvertisementError(
+      const BroadcastAdvertisementCallback& callback,
+      int32_t adv_handle,
+      device::BluetoothAdvertisement::ErrorCode error_code);
+  // Both of the following are called after we've tried to unregister
+  // the advertisement for |adv_handle|. Either way, we will no
+  // longer be broadcasting this advertisement, so in either case, the
+  // handle can be released.
+  void OnUnregisterAdvertisementDone(
+      const ReleaseAdvertisementHandleCallback& callback,
+      int32_t adv_handle);
+  void OnUnregisterAdvertisementError(
+      const ReleaseAdvertisementHandleCallback& callback,
+      int32_t adv_handle,
+      device::BluetoothAdvertisement::ErrorCode error_code);
+  // Find the next free advertisement handle and put it in *adv_handle,
+  // or return false if the advertisement map is full.
+  bool GetAdvertisementHandle(int32_t* adv_handle);
+
   bool CalledOnValidThread();
 
   mojo::Binding<mojom::BluetoothHost> binding_;
@@ -411,6 +459,21 @@ class ArcBluetoothBridge
   // Timer to turn adapter discoverable off.
   base::OneShotTimer discoverable_off_timer_;
 
+  // Holds advertising data registered by the instance.
+  //
+  // When a handle is reserved, an entry is placed into the advertisements_
+  // map. This entry is not yet associated with a device::BluetoothAdvertisement
+  // because the instance hasn't sent us any advertising data yet, so its
+  // mapped value is nullptr until that happens. Thus we have three states for a
+  // handle:
+  // * unmapped -> free
+  // * mapped to nullptr -> reserved, awaiting data
+  // * mapped to a device::BluetoothAdvertisement -> in use, and the mapped
+  //   BluetoothAdvertisement is currently registered with the adapter.
+  static constexpr uint16_t kMaxAdvertisements = 5;

[Rahul Chaturvedi, 2016/09/16 22:37:22]

Is there a requirement for this to be 5? If not, let's keep this number at 3 or
4, to allow for Chrome OS to also be advertising at the same time.

[Rahul Chaturvedi, 2016/09/16 22:37:22]

Don't use static constexpr's in classes for integer values. Use enum {
kMaxAdvertisements = 5; } instead.

This thread has details if you are curious:
https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/hDqJ4KBVqog

+  std::map<int32_t, scoped_refptr<device::BluetoothAdvertisement>>
+      advertisements_;
+
   base::ThreadChecker thread_checker_;
 
   // WeakPtrFactory to use for callbacks.