Revert of [AudioPlayer] Enable new audio-player by default (https://codereview.chromium.org/136783007/)

Reason for revert:
The trybots here and on the waterfall are failing 
browser_tests:
OpenSpecialTypes/FileManagerBrowserTest.Test/3
OpenSpecialTypes/FileManagerBrowserTest.Test/4
OpenSpecialTypes/FileManagerBrowserTest.Test/5

Please ensure your tests pass trybots before landing manually!!!

http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%282%29/builds/21336

BrowserTestBase signal handler received SIGTERM. Backtrace:
 [0x7fdb4ea60f8e] base::debug::StackTrace::StackTrace()
 [0x00000298302b] content::(anonymous namespace)::DumpStackTraceSignalHandler()
 [0x7fdb463b94a0] \u003Cunknown>
 [0x7fdb4646ba43] __poll
 [0x7fdb45cc0ff6] \u003Cunknown>
 [0x7fdb45cc1124] g_main_context_iteration
 [0x7fdb4ea45bdf] base::MessagePumpGlib::RunWithDispatcher()
 [0x7fdb4eaa1970] base::MessageLoop::RunHandler()
 [0x7fdb4eacd0f8] base::RunLoop::Run()
 [0x0000029bf9dc] content::RunThisRunLoop()
 [0x0000029bfa34] content::RunMessageLoop()
 [0x0000006aedc5] file_manager::(anonymous namespace)::FileManagerBrowserTest_Test_Test::RunTestOnMainThread()
 [0x0000019be6ea] InProcessBrowserTest::RunTestOnMainThreadLoop()
 [0x000002b2d362] ChromeBrowserMainParts::PreMainMessageLoopRunImpl()
 [0x000002b2e2f3] ChromeBrowserMainParts::PreMainMessageLoopRun()
 [0x000002597214] chromeos::ChromeBrowserMainPartsChromeos::PreMainMessageLoopRun()
 [0x7fdb4b5703a4] content::BrowserMainLoop::PreMainMessageLoopRun()
 [0x7fdb4b86db90] content::StartupTaskRunner::RunAllTasksNow()
 [0x7fdb4b5762e6] content::BrowserMainLoop::CreateStartupTasks()
 [0x7fdb4b578850] content::BrowserMainRunnerImpl::Initialize()
 [0x7fdb4b56f354] content::BrowserMain()
 [0x0000029836e1] content::BrowserTestBase::SetUp()
 [0x0000019bdb6c] InProcessBrowserTest::SetUp()
 [0x000001a82e8a] testing::Test::Run()
 [0x000001a82fca] testing::TestInfo::Run()
 [0x000001a8310f] testing::TestCase::Run()
 [0x000001a8339f] testing::internal::UnitTestImpl::RunAllTests()
 [0x000001a7d323] testing::UnitTest::Run()
 [0x0000019d848e] base::TestSuite::Run()
 [0x0000019bc3b5] (anonymous namespace)::ChromeTestLauncherDelegate::RunTestSuite()
 [0x0000029ba677] content::LaunchTests()
 [0x0000019bc458] LaunchChromeTests()
 [0x7fdb463a476d] __libc_start_main
 [0x00000053d6d9] \u003Cunknown>


Original issue's description:
> [AudioPlayer] Enable new audio-player by default
> 
> This patch is reland of r248688, fixing the test failures.
> 
> BUG=273308
> TEST=manually tested
> R=hirono@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=248758

TBR=hirono@chromium.org,yoshiki@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=273308

Review URL: https://codereview.chromium.org/154193002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248777 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248777