Revert r223961 and r224074 (using IO message loop instead of DEFAULT).

MessagePumpDefault was incorrectly using system time instead of monotonic time
for PostDelayedTask. This was fixed in r226378 so we don't need this workaround
any more.

BUG=293736

Review URL: https://codereview.chromium.org/25628004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226425 0039d316-1c4b-4281-b951-d872f2087c98

content/renderer/render_thread_impl.cc

@@ -653,18 +653,7 @@ void RenderThreadImpl::EnsureWebKitInitialized() {
 #endif
     if (!compositor_message_loop_proxy_.get()) {
       compositor_thread_.reset(new base::Thread("Compositor"));
-#if defined(OS_POSIX)
-      // Workaround for crbug.com/293736
-      // On Posix, MessagePumpDefault uses system time, so delayed tasks (for
-      // compositor scheduling) work incorrectly across system time changes
-      // (e.g.  tlsdate). So instead, use an IO loop, which uses libevent, that
-      // uses monotonic time (immune to these problems).
-      base::Thread::Options options;
-      options.message_loop_type = base::MessageLoop::TYPE_IO;
-      compositor_thread_->StartWithOptions(options);
-#else
       compositor_thread_->Start();
-#endif
 #if defined(OS_ANDROID)
       compositor_thread_->SetPriority(base::kThreadPriority_Display);
 #endif
@@ -1282,18 +1271,7 @@ RenderThreadImpl::GetMediaThreadMessageLoopProxy() {
   DCHECK(message_loop() == base::MessageLoop::current());
   if (!media_thread_) {
     media_thread_.reset(new base::Thread("Media"));
-#if defined(OS_POSIX)
-    // Workaround for crbug.com/293736
-    // On Posix, MessagePumpDefault uses system time, so delayed tasks (for
-    // compositor scheduling) work incorrectly across system time changes
-    // (e.g.  tlsdate). So instead, use an IO loop, which uses libevent, that
-    // uses monotonic time (immune to these problems).
-    base::Thread::Options options;
-    options.message_loop_type = base::MessageLoop::TYPE_IO;
-    media_thread_->StartWithOptions(options);
-#else
     media_thread_->Start();
-#endif
 
 #if defined(OS_ANDROID)
     renderer_demuxer_ = new RendererDemuxerAndroid();

ui/compositor/compositor.cc

@@ -507,18 +507,7 @@ void Compositor::Initialize() {
 #endif
   if (use_thread) {
     g_compositor_thread = new base::Thread("Browser Compositor");
-#if defined(OS_POSIX)
-    // Workaround for crbug.com/293736
-    // On Posix, MessagePumpDefault uses system time, so delayed tasks (for
-    // compositor scheduling) work incorrectly across system time changes (e.g.
-    // tlsdate). So instead, use an IO loop, which uses libevent, that uses
-    // monotonic time (immune to these problems).
-    base::Thread::Options options;
-    options.message_loop_type = base::MessageLoop::TYPE_IO;
-    g_compositor_thread->StartWithOptions(options);
-#else
     g_compositor_thread->Start();
-#endif
   }
 
   DCHECK(!g_compositor_initialized) << "Compositor initialized twice.";