Remove systrace from tools.atree

Systrace should be released along with every platform release.

Change-Id: Ic6c728906aa6af01ca98200a18dd4685d403f3e0
diff --git a/build/tools.atree b/build/tools.atree
index e413484..fa98a7b 100644
--- a/build/tools.atree
+++ b/build/tools.atree
@@ -132,14 +132,6 @@
 # tools specific support jar
 framework/annotations.jar               tools/support/annotations.jar
 
-# systrace
-external/chromium-trace/systrace.py     tools/systrace/systrace.py
-external/chromium-trace/script.js       tools/systrace/script.js
-external/chromium-trace/style.css       tools/systrace/style.css
-external/chromium-trace/LICENSE         tools/systrace/LICENSE
-external/chromium-trace/AUTHORS         tools/systrace/AUTHORS
-external/chromium-trace/NOTICE          tools/systrace/NOTICE
-
 # Misspelling databases for lint
 sdk/files/typos                         tools/support