Revert r156303 as non-Aura Metro mode is gone

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index ddf8f43d88a1b23a761e71520d6ab1f10ff363fe..a59cece6a7545b3c7360ba7d193baf72620d2576 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -581,10 +581,6 @@ const char kEnableServiceWorker[]           = "enable-service-worker";
 // SYN packet.
 const char kEnableTcpFastOpen[]             = "enable-tcp-fastopen";
 
-// Enable Text Service Framework(TSF) for text inputting instead of IMM32. This
-// flag is ignored on Metro environment.
-const char kEnableTextServicesFramework[]   = "enable-text-services-framework";
-
 // Enable multithreaded GPU compositing of web content.
 const char kEnableThreadedCompositing[]     = "enable-threaded-compositing";