device/bluetooth: Add I/O watcher for audio data retrieval triggered by state change.

chromeos/dbus/fake_bluetooth_media_transport_client.h

Index: chromeos/dbus/fake_bluetooth_media_transport_client.h
diff --git a/chromeos/dbus/fake_bluetooth_media_transport_client.h b/chromeos/dbus/fake_bluetooth_media_transport_client.h
index 319b2ae3c4e0518d527936f0c323e82f87d71856..d4b162aea442d43c9d0dd92bfef96de10c3fa0d8 100644
--- a/chromeos/dbus/fake_bluetooth_media_transport_client.h
+++ b/chromeos/dbus/fake_bluetooth_media_transport_client.h
@@ -9,6 +9,7 @@
 #include <string>
 #include <vector>
 
+#include "base/files/file.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
 #include "chromeos/chromeos_export.h"
@@ -76,7 +77,12 @@ class CHROMEOS_EXPORT FakeBluetoothMediaTransportClient
   void SetVolume(const dbus::ObjectPath& endpoint_path,
                  const uint16_t& volume);
 
-  // Gets the transport path associated with the given endpoint path.
+  // Writes bytes to the input file descriptor, |input_fd|, associated with a
+  // transport object which is bound to |endpoint_path|.
+  void WriteData(const dbus::ObjectPath& endpoint_path,
+                 const std::vector<char>& bytes);
+
+  // Retrieves the transport object path bound to |endpoint_path|.
   dbus::ObjectPath GetTransportPath(const dbus::ObjectPath& endpoint_path);
 
   // Gets the endpoint path associated with the given transport_path.
@@ -86,8 +92,7 @@ class CHROMEOS_EXPORT FakeBluetoothMediaTransportClient
   // This class is used for simulating the scenario where each media endpoint
   // has a corresponding transport path and properties. Once an endpoint is
   // assigned with a transport path, an object of Transport is created.
-  class Transport {
-   public:
+  struct Transport {
     Transport(const dbus::ObjectPath& transport_path,
               Properties* transport_properties);
     ~Transport();
@@ -97,11 +102,18 @@ class CHROMEOS_EXPORT FakeBluetoothMediaTransportClient
 
     // The property set bound with |path|.
     scoped_ptr<Properties> properties;
+
+    // This is the internal end of socketpair created for simulation purposes.
+    // |input_fd| will be initialized when Acquire/TryAcquire is called.
+    scoped_ptr<base::File> input_fd;
   };
 
   // Property callback passed while a Properties structure is created.
   void OnPropertyChanged(const std::string& property_name);
 
+  // Retrieves the transport structure bound to |endpoint_path|
+  Transport* GetTransport(const dbus::ObjectPath& endpoint_path);
+
   // Map of endpoints with valid transport. Each pair is composed of an endpoint
   // path and a Transport structure containing a transport path and its
   // properties.
@@ -112,9 +124,6 @@ class CHROMEOS_EXPORT FakeBluetoothMediaTransportClient
   // corresponding endpoint path when GetProperties() is called.
   std::map<dbus::ObjectPath, dbus::ObjectPath> transport_to_endpoint_map_;
 
-  // The path of the media transport object.
-  dbus::ObjectPath object_path_;
-
   ObserverList<BluetoothMediaTransportClient::Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeBluetoothMediaTransportClient);