Set the application name

This CL sets the application name so that it is easier to look up
mtplot in the window manager.

BUG=chromium:216295
TEST=Follow steps below:
$ mtplot -d :0
$ DISPLAY=:0 xwininfo -root -tree

It would show something like
     0x600001 "mtplot": ()  1280x800+0+0  +0+0
rather than
     0x600001 (has no name): ()  1280x800+0+0  +0+0

Change-Id: Ifd8de8b72e566d31eb98c4e8f4c96c83084b7d68
Reviewed-on: https://gerrit.chromium.org/gerrit/32219
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Tested-by: Joseph Shyh-In Hwang <josephsih@chromium.org>
Commit-Queue: Joseph Shyh-In Hwang <josephsih@chromium.org>
diff --git a/mtplot.c b/mtplot.c
index 17d08cb..49608d3 100644
--- a/mtplot.c
+++ b/mtplot.c
@@ -513,6 +513,9 @@
   w = XCreateSimpleWindow(dpy, DefaultRootWindow(dpy), x, y, w_width, w_height,
                           0, blackColor, blackColor);
 
+  // Set the application name so that it is easier to look up in window manager.
+  XStoreName(dpy, w, "mtplot");
+
   // We want to get MapNotify events
   XSelectInput(dpy, w, StructureNotifyMask | KeyPressMask);