content: Improve thread priority for raster threads.

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 21330fee0d16efb5ff321d818578b54014849ecc..7518dc8727d8f3f74e6190a193648062a8961593 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -831,11 +831,6 @@ const char kVideoImageTextureTarget[] = "video-image-texture-target";
 // Set when Chromium should use a mobile user agent.
 const char kUseMobileUserAgent[] = "use-mobile-user-agent";
 
-// Use normal priority for tile task worker threads.  Otherwise they may
-// be run at background priority on some platforms.
-const char kUseNormalPriorityForTileTaskWorkerThreads[] =
-    "use-normal-priority-for-tile-task-worker-threads";
-
 // Use remote compositor for the renderer.
 const char kUseRemoteCompositing[] = "use-remote-compositing";