Enable logging in mojo:media app.

mojo/services/html_viewer/html_viewer.cc

Index: mojo/services/html_viewer/html_viewer.cc
diff --git a/mojo/services/html_viewer/html_viewer.cc b/mojo/services/html_viewer/html_viewer.cc
index fc69d33810ce241e1e3031db967b7ffbb00d3666..77e34ba0ed5598b3ce8e08e1c43a689c66d7aad5 100644
--- a/mojo/services/html_viewer/html_viewer.cc
+++ b/mojo/services/html_viewer/html_viewer.cc
@@ -170,6 +170,8 @@ class HTMLViewer : public mojo::ApplicationDelegate,
     logging::LoggingSettings settings;
     settings.logging_dest = logging::LOG_TO_SYSTEM_DEBUG_LOG;
     logging::InitLogging(settings);
+    // Display process ID, thread ID and timestamp in logs.
+    logging::SetLogItems(true, true, true, false);
 
     bool enable_mojo_media_renderer =
         command_line->HasSwitch(kEnableMojoMediaRenderer);