Remove v8 source dependency, enable more compiler warnings

deps/all.deps/DEPS

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 vars = {
   # Use this googlecode_url variable only if there is an internal mirror for it.
   # If you do not know, use the full path while defining your new deps entry.
   "googlecode_url": "http://%s.googlecode.com/svn",
 
   "gyp_rev": "@1495",
   "nss_rev": "@169195",
   "co19_rev": "@515",
   "co19_repo": "http://co19.googlecode.com/svn/trunk/co19/",
   "chromium_url": "http://src.chromium.org/svn",
   "chromium_git": "http://git.chromium.org/git",
-  "v8_release": "3.15",
 
   # Revisions of /third_party/* dependencies.
   "7zip_rev" : "@19997",
   "apache_ant_rev" : "@19997",
   "apache_compress_rev" : "@19997",
   "args4j_rev" : "@19997",
   "bzip2_rev" : "@19997",
   "chrome_rev" : "@19997",
   "commons-io_rev" : "@19997",
   "commons-lang_rev" : "@19997",
@@ skipping 14 matching lines @@
 }
 
 deps = {
   "dart":
     "/branches/bleeding_edge/dart",
 
   # Stuff needed for GYP to run.
   "dart/third_party/gyp":
       (Var("googlecode_url") % "gyp") + "/trunk" + Var("gyp_rev"),
 
-  "dart/third_party/v8":
-      (Var("googlecode_url") % "v8") + "/branches/" + Var("v8_release"),
-
   "dart/tests/co19/src":
     Var("co19_repo") + "tests/co19/src" + Var("co19_rev"),
 
   "dart/third_party/nss":
       Var("chromium_url") + "/trunk/deps/third_party/nss" + Var("nss_rev"),
 
   "dart/third_party/sqlite":
       Var("chromium_url") + "/trunk/src/third_party/sqlite" + Var("nss_rev"),
 
   "dart/third_party/zlib":
@@ skipping 56 matching lines @@
   },
   {
     "pattern": ".",
     "action": ["python", "dart/editor/build/generate_sources.py"],
   },
   {
     "pattern": ".",
     "action": ["python", "dart/tools/gyp_dart.py"],
   },
 ]