Update to latest trace-viewer (a7f1c1b3)

Includes rewrite of prefix.html to switch from TraceViewer
to timeline-view, and account for new location of the
vulcanizer.

Cherry-pick of ced05db70069f9d84c4b0dd9b3b26b94e3482336 from AOSP

Change-Id: I07285c64bde7d4bfe414c9e93b097435e118a069
diff --git a/trace-viewer/PRESUBMIT.py b/trace-viewer/PRESUBMIT.py
index f7df077..38bad96 100644
--- a/trace-viewer/PRESUBMIT.py
+++ b/trace-viewer/PRESUBMIT.py
@@ -4,13 +4,18 @@
 
 import sys
 
+def RunChecks(input_api, output_api):
+  results = []
+  from build import presubmit_checks
+  results += presubmit_checks.RunChecks(input_api)
+
+  return map(output_api.PresubmitError, results)
 
 def CheckChange(input_api, output_api):
   original_sys_path = sys.path
   try:
     sys.path += [input_api.PresubmitLocalPath()]
-    from hooks import pre_commit
-    return pre_commit.RunChecks(input_api, output_api)
+    return RunChecks(input_api, output_api)
   finally:
     sys.path = original_sys_path