Update revision info to version info for dart2js et al.

tools/utils.py

Index: tools/utils.py
===================================================================
--- tools/utils.py	(revision 13566)
+++ tools/utils.py	(working copy)
@@ -152,6 +152,14 @@
 def GetBaseDir():
   return BASE_DIR
 
+def GetVersion():
+  dartbin = DartBinary()
+  version_script = VersionScript()
+  p = subprocess.Popen([dartbin, version_script], stdout = subprocess.PIPE,
+      stderr = subprocess.STDOUT, shell=IsWindows())
+  output, not_used = p.communicate()
+  return output.strip()
+
 def GetSVNRevision():
   p = subprocess.Popen(['svn', 'info'], stdout = subprocess.PIPE,
       stderr = subprocess.STDOUT, shell=IsWindows())
@@ -297,6 +305,11 @@
     os.utime(name, None)
 
 
+def VersionScript():
+  tools_dir = os.path.dirname(os.path.realpath(__file__))
+  return os.path.join(tools_dir, 'version.dart')
+
+
 def DartBinary():
   tools_dir = os.path.dirname(os.path.realpath(__file__))
   dart_binary_prefix = os.path.join(tools_dir, 'testing', 'bin')