Enable new getUserMedia audio constraints algorithm behind a flag.

extensions/browser/guest_view/web_view/web_view_media_access_apitest.cc

Index: extensions/browser/guest_view/web_view/web_view_media_access_apitest.cc
diff --git a/extensions/browser/guest_view/web_view/web_view_media_access_apitest.cc b/extensions/browser/guest_view/web_view/web_view_media_access_apitest.cc
index c013665c062d2e4c75d6d37fa6eb353ef9142c9f..7e3dbb67570676232df965c09f1f19c8e6feb924 100644
--- a/extensions/browser/guest_view/web_view/web_view_media_access_apitest.cc
+++ b/extensions/browser/guest_view/web_view/web_view_media_access_apitest.cc
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/command_line.h"
 #include "base/macros.h"
 #include "base/strings/stringprintf.h"
 #include "content/public/browser/web_contents_delegate.h"
@@ -80,6 +81,11 @@ class WebViewMediaAccessAPITest : public WebViewAPITest {
         base::StringPrintf("runTest('%s');", test_name.c_str())));
     ASSERT_TRUE(test_run_listener.WaitUntilSatisfied());
   }
+
+  void SetUpCommandLine(base::CommandLine* command_line) override {
+    WebViewAPITest::SetUpCommandLine(command_line);
+    command_line->AppendSwitch("use-fake-device-for-media-stream");

[hbos_chromium, 2017/06/16 17:27:14]

Why is this needed if it wasn't before?

[Guido Urdaneta, 2017/06/19 11:56:49]

Because the old code first asked for permission and then did constraints
processing.
The new code does constraints processing first and, if there are no devices,
getUserMedia fails without asking for permission, as the spec says it should.
This test relies on getUserMedia always asking for permission, which can be
guaranteed with fake devices.
Many bots have no real devices, so the test would fail there otherwise.

[hbos_chromium, 2017/06/19 15:14:42]

Acknowledged.

+  }
 };
 
 IN_PROC_BROWSER_TEST_F(WebViewMediaAccessAPITest, TestAllow) {