linux_aura: Improve window drag performance.

chrome/browser/ui/aura/tabs/dock_info_auralinux.cc

Index: chrome/browser/ui/aura/tabs/dock_info_auralinux.cc
diff --git a/chrome/browser/ui/aura/tabs/dock_info_auralinux.cc b/chrome/browser/ui/aura/tabs/dock_info_auralinux.cc
index d43de3baab635b0ee33c63751fcf5bcd0f666c87..c26d04622178d1bc1e46e88a67bbb1d6a9256b1b 100644
--- a/chrome/browser/ui/aura/tabs/dock_info_auralinux.cc
+++ b/chrome/browser/ui/aura/tabs/dock_info_auralinux.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/ui/tabs/dock_info.h"
 
+#include "base/debug/trace_event.h"
 #include "chrome/browser/ui/host_desktop.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
@@ -179,6 +180,9 @@ gfx::NativeView DockInfo::GetLocalProcessWindowAtPoint(
     chrome::HostDesktopType host_desktop_type,
     const gfx::Point& screen_point,
     const std::set<gfx::NativeView>& ignore) {
+  TRACE_EVENT1("ui", "DockInfo::GetLocalProcessWindowAtPoint",
+               "screen_point", screen_point.ToString());
+
   // The X11 server is the canonical state of what the window stacking order
   // is.
   XID xid =