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");

[Devlin, 2017/06/21 13:14:33]

nit: maybe add a comment explaining why this is necessary?

[Devlin, 2017/06/21 13:14:33]

Can we use the kUseFakeDeviceForMediaStream constant?

[Guido Urdaneta, 2017/06/21 14:54:56]

will do in the next patchset.

[Guido Urdaneta, 2017/06/21 14:54:56]

No, due to layering rules. 

[Devlin, 2017/06/21 19:21:26]

Using the value of a constant doesn't make it less of a layering violation. :) 
But since this is just a test, I'd be fine with adding a DEPS file to
extensions/browser/guest_view/web_view with

specific_include_rules = {
  ".*(test)\.(cc|h)$": [
    "+media", # Tests need to be able to tweak media devices.
  ]
}

[Guido Urdaneta, 2017/06/22 09:30:13]

Done. I thought using the string directly was OK too since that string is a
public API available to users outside the source code.
Didn't know about specific_include_rules, though :)

+  }
 };
 
 IN_PROC_BROWSER_TEST_F(WebViewMediaAccessAPITest, TestAllow) {