Remove dartc optimizing backend.

deps/dartium.deps/DEPS

 vars = {
   # Additions for Dart
   "chromium_url": "http://src.chromium.org/svn",
   "chromium_revision": "119649",
   # The Dart repository URL is pulled out here so that it can be easily
   # updated to "https" for committers.
   "dart_url": "http://dart.googlecode.com/svn",
   "multivm_url": "http://src.chromium.org/multivm/trunk",
   "dartium_chromium_revision": "29",
   "dartium_webkit_trunk": "http://src.chromium.org/multivm/trunk/webkit",
@@ skipping 47 matching lines @@
 }
 
 deps = {
   # Additions for Dart
   "src":
     Var("chromium_url") + "/trunk/src@" + Var("chromium_revision"),
 
   "src/dart":
     Var("dart_url") + "/branches/bleeding_edge/dart",
 
-  "src/dart/third_party/closure_compiler_src":
-    "http://closure-compiler.googlecode.com/svn/trunk@1519",
-
   "src/dartium_tools":
     Var("multivm_url") + "/tools@" + Var("dartium_tools_revision"),
 
   "src/breakpad/src":
     (Var("googlecode_url") % "google-breakpad") + "/trunk/src@907",
 
   "src/build/util/support":
     Var("chromium_url") + "/trunk/deps/support@20411",
 
   "src/googleurl":
@@ skipping 432 matching lines @@
     # which takes ~20s, but clang speeds up builds by more than 20s.
     "pattern": ".",
     "action": ["python", "src/tools/clang/scripts/update.py", "--mac-only"],
   },
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     "pattern": ".",
     "action": ["python", "src/build/gyp_chromium"],
   },
 ]