Re-add kUseGpuInTests flag in WebRTC browser tests.

chrome/browser/media/chrome_webrtc_simulcast_browsertest.cc

 // Copyright 2015 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/files/file_path.h"
 #include "base/path_service.h"
 #include "chrome/browser/media/webrtc_browsertest_base.h"
 #include "chrome/browser/media/webrtc_browsertest_common.h"
 #include "chrome/browser/ui/browser.h"
@@ skipping 15 matching lines @@
 // Simulcast integration test. This test ensures 'a=x-google-flag:conference'
 // is working and that Chrome is capable of sending simulcast streams.
 class WebRtcSimulcastBrowserTest : public WebRtcTestBase {
  public:
   // TODO(phoglund): Make it possible to enable DetectErrorsInJavaScript() here.
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
     // Just answer 'allow' to GetUserMedia invocations.
     command_line->AppendSwitch(switches::kUseFakeUIForMediaStream);
 
+    // The video playback will not work without a GPU, so force its use here.
+    command_line->AppendSwitch(switches::kUseGpuInTests);
+
     // Use fake devices in order to run on VMs.
     command_line->AppendSwitch(switches::kUseFakeDeviceForMediaStream);
   }
 };
 
 // Fails/times out on Win only.  http://crbug.com/452623
 #if defined(OS_WIN)
 #define MAYBE_TestVgaReturnsTwoSimulcastStreams DISABLED_TestVgaReturnsTwoSimulcastStreams
 #else
 #define MAYBE_TestVgaReturnsTwoSimulcastStreams TestVgaReturnsTwoSimulcastStreams
 #endif
 IN_PROC_BROWSER_TEST_F(WebRtcSimulcastBrowserTest,
                        MAYBE_TestVgaReturnsTwoSimulcastStreams) {
   ASSERT_TRUE(embedded_test_server()->InitializeAndWaitUntilReady());
 
   ui_test_utils::NavigateToURL(
       browser(), embedded_test_server()->GetURL(kSimulcastTestPage));
 
   content::WebContents* tab_contents =
       browser()->tab_strip_model()->GetActiveWebContents();
 
   ASSERT_EQ("OK", ExecuteJavascript("testVgaReturnsTwoSimulcastStreams()",
                                     tab_contents));
 }