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(
+        profile()->GetResourceContext(),
+        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