Remove all but one use of WeakPtrFactory::DetachFromThread.

ui/gl/gl_surface_glx.cc

Index: ui/gl/gl_surface_glx.cc
diff --git a/ui/gl/gl_surface_glx.cc b/ui/gl/gl_surface_glx.cc
index 87dffe9e5ba8f450c9ebcafc2fb43319096cdcf8..b2f9cf99f0e9fcfd0201886773e22c9c40f7a916 100644
--- a/ui/gl/gl_surface_glx.cc
+++ b/ui/gl/gl_surface_glx.cc
@@ -240,9 +240,6 @@ class SGIVideoSyncVSyncProvider
         shim_((new SGIVideoSyncProviderThreadShim(window))->AsWeakPtr()),
         cancel_vsync_flag_(shim_->cancel_vsync_flag()),
         vsync_lock_(shim_->vsync_lock()) {
-    // The WeakPtr is bound to the SGIVideoSyncThread. We only use it for
-    // PostTask.
-    shim_->DetachFromThread();
     vsync_thread_->message_loop()->PostTask(
         FROM_HERE,
         base::Bind(&SGIVideoSyncProviderThreadShim::Initialize, shim_));