Enable new getUserMedia audio constraints algorithm behind a flag.

extensions/browser/guest_view/web_view/web_view_media_access_apitest.cc

 // Copyright 2014 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/command_line.h"
 #include "base/macros.h"
 #include "base/strings/stringprintf.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/test/browser_test_utils.h"
 #include "extensions/browser/guest_view/web_view/web_view_apitest.h"
 #include "extensions/test/extension_test_message_listener.h"
 
 namespace {
 
 // This class intercepts media access request from the embedder. The request
@@ skipping 58 matching lines @@
 
   // Runs media_access tests.
   void RunTest(const std::string& test_name) {
     ExtensionTestMessageListener test_run_listener("TEST_PASSED", false);
     test_run_listener.set_failure_message("TEST_FAILED");
     EXPECT_TRUE(content::ExecuteScript(
         embedder_web_contents_,
         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) {
   std::string app_location = "web_view/media_access/allow";
   StartTestServer(app_location);
   LaunchApp(app_location);
 
   std::unique_ptr<MockWebContentsDelegate> mock(new MockWebContentsDelegate());
   embedder_web_contents_->SetDelegate(mock.get());
 
@@ skipping 99 matching lines @@
                        TestNoPreventDefaultImpliesDeny) {
   std::string app_location = "web_view/media_access/deny";
   StartTestServer(app_location);
   LaunchApp(app_location);
 
   RunTest("testNoPreventDefaultImpliesDeny");
   StopTestServer();
 }
 
 }  // namespace extensions