Implement a salt for MediaSource IDs that can be cleared by a user.

chrome/browser/extensions/api/webrtc_audio_private/webrtc_audio_private_browsertest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/json/json_writer.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/stringprintf.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/platform_thread.h"
 #include "base/time/time.h"
@@ skipping 232 matching lines @@
   // Get the list of input devices. We can cheat in the unit test and
   // run this on the main thread since nobody else will be running at
   // the same time.
   AudioDeviceNames devices;
   GetAudioDeviceNames(&AudioManager::GetAudioInputDeviceNames, &devices);
 
   // Try to get an associated sink for each source.
   for (AudioDeviceNames::const_iterator device = devices.begin();
        device != devices.end();
        ++device) {
+
+    scoped_refptr<WebrtcAudioPrivateGetAssociatedSinkFunction> function =
+        new WebrtcAudioPrivateGetAssociatedSinkFunction();
+
     std::string raw_source_id = device->unique_id;
     VLOG(2) << "Trying to find associated sink for device " << raw_source_id;
     GURL origin(GURL("http://www.google.com/").GetOrigin());
-    std::string source_id_in_origin =
-        content::GetHMACForMediaDeviceID(origin, raw_source_id);
+    std::string source_id_in_origin = content::GetHMACForMediaDeviceID(
+        function->GetProfile()->GetResourceContext(),

[Jói, 2013/11/05 14:14:08]

I don't know for sure, but I would think function->GetProfile here is going to
be NULL, since I don't think you have initialized it in any way. When function
objects are created by the extension system, that's different I believe since
they probably go through more initialization.

In an ExtensionAPITest (which this is) you can directly call profile()
(inherited from somewhere up the class hierarchy) to get the current profile.

[perkj_chrome, 2013/11/05 16:25:06]

Done.

+        origin,
+        raw_source_id);
 
     ListValue parameters;
     parameters.AppendString(origin.spec());
     parameters.AppendString(source_id_in_origin);
     std::string parameter_string;
     JSONWriter::Write(&parameters, &parameter_string);
 
-    scoped_refptr<WebrtcAudioPrivateGetAssociatedSinkFunction> function =
-        new WebrtcAudioPrivateGetAssociatedSinkFunction();
+
     scoped_ptr<base::Value> result(
         RunFunctionAndReturnSingleResult(function.get(),
                                          parameter_string,
                                          browser()));
     std::string result_string;
     JSONWriter::Write(result.get(), &result_string);
     VLOG(2) << "Results: " << result_string;
   }
 }
 
@@ skipping 10 matching lines @@
       test_data_dir_.AppendASCII("webrtc_audio_private_event_listener"));
   service->OnDevicesChanged(base::SystemMonitor::DEVTYPE_AUDIO_CAPTURE);
 
   // Check that the extension got the notification.
   std::string result = ExecuteScriptInBackgroundPage(extension->id(),
                                                      "reportIfGot()");
   EXPECT_EQ("true", result);
 }
 
 }  // namespace extensions