Generate snapshot for dartj2s; use it in the SDK.

dart/tools/create_sdk.py

Index: dart/tools/create_sdk.py
diff --git a/dart/tools/create_sdk.py b/dart/tools/create_sdk.py
index 0543b647c23d4695fac9eccd0484d1714ad51284..a0b51a431b50d8a5c67a354145a83b5496923605 100755
--- a/dart/tools/create_sdk.py
+++ b/dart/tools/create_sdk.py
@@ -131,6 +131,15 @@ def CopyDart2Js(build_dir, sdk_root, version):
     ReplaceInFiles([dartdoc],
                    [(r'\$BIN_DIR/\.\./\.\.', r'$BIN_DIR/..')])
 
+    # TODO(ahe): Enable for Windows as well.
+    subprocess.call([os.path.join(build_dir, 'gen_snapshot'),
+                     '--script_snapshot=%s' %
+                     os.path.join(sdk_root, 'pkg', 'compiler',
+                                  'implementation', 'dart2js.dart.snapshot'),
+                     os.path.join(sdk_root, 'pkg', 'compiler',
+                                  'implementation', 'dart2js.dart')])
+
+
 
 def Main(argv):
   # Pull in all of the gpyi files which will be munged into the sdk.