[DO NOT COMMIT] Refactor systrace to support new clock sync design

systrace/systrace/update_systrace_trace_viewer.py

Index: systrace/systrace/update_systrace_trace_viewer.py
diff --git a/systrace/systrace/update_systrace_trace_viewer.py b/systrace/systrace/update_systrace_trace_viewer.py
index 09eb0553298fbcdf337611c7e25c801a8d30d24a..ae255fbd2097037acbf0e679be0ce85fbdee529f 100755
--- a/systrace/systrace/update_systrace_trace_viewer.py
+++ b/systrace/systrace/update_systrace_trace_viewer.py
@@ -47,7 +47,7 @@ def get_catapult_rev_in_git_():
     return ''
 
 
-def update(no_auto_update=False, no_min=False):
+def update(dest=None, no_auto_update=False, no_min=False):
   """Update the systrace trace viewer html file.
 
   When the html file exists, do not update the file if
@@ -55,6 +55,7 @@ def update(no_auto_update=False, no_min=False):
   2. or the revision is not changed.
 
   Args:
+    dest:           Directory to put the systrace_trace_viewer.html file.
     no_auto_update: If true, force updating the file with revision
                     NO_AUTO_UPDATE_. Future updates will be skipped unless this
                     argument is true again.
@@ -74,7 +75,7 @@ def update(no_auto_update=False, no_min=False):
         return
 
   # Generate the vulcanized result.
-  output_html_file = SYSTRACE_TRACE_VIEWER_HTML_FILE_
+  output_html_file = os.path.join(dest, SYSTRACE_TRACE_VIEWER_HTML_FILE_)
   with codecs.open(output_html_file, encoding='utf-8', mode='w') as f:
     vulcanize_trace_viewer.WriteTraceViewer(
         f,