Multivm branch: Fetch reference build from archive using git hash, not revision.

dart/tools/bots/get_chromium_build.py

Index: dart/tools/bots/get_chromium_build.py
===================================================================
--- dart/tools/bots/get_chromium_build.py	(revision 37731)
+++ dart/tools/bots/get_chromium_build.py	(working copy)
@@ -14,6 +14,7 @@
   $ get_chromium_build.py -r <revision> -t <target>
 """
 
+import json
 import logging
 import optparse
 import os
@@ -49,7 +50,7 @@
     self._zipfiles = platform_data['zipfiles']
     self._folder = platform_data['folder']
     self._archive_path = platform_data['archive_path']
-    self._revision = int(options.revision)
+    self._revision = options.revision
     self._target_dir = options.target_dir
     self._download_dir = os.path.join(self._target_dir, 'downloads')
 
@@ -57,12 +58,9 @@
     return CHROMIUM_URL_FMT % (self._archive_path, revision, filename)
 
   def _FindBuildRevision(self, revision, filename):
-    MAX_REVISIONS_PER_BUILD = 100
-    for revision_guess in xrange(revision, revision + MAX_REVISIONS_PER_BUILD):
-      if self._DoesBuildExist(revision_guess, filename):
-        return revision_guess
-      else:
-        time.sleep(.1)
+    git_hash = json.loads(revision)[platform.system()]
+    if self._DoesBuildExist(git_hash, filename):
+      return git_hash
     return None
 
   def _DoesBuildExist(self, revision_guess, filename):