Allowing optional build of a WASM prototype behind a gyp define.

DEPS

 # Note: The buildbots evaluate this file with CWD set to the parent
 # directory and assume that the root of the checkout is in ./v8/, so
 # all paths in here must match this assumption.
 
 vars = {
   "git_url": "https://chromium.googlesource.com",
 }
 
 deps = {
   "v8/build/gyp":
     Var("git_url") + "/external/gyp.git" + "@" + "6ee91ad8659871916f9aa840d42e1513befdf638",
   "v8/third_party/icu":
     Var("git_url") + "/chromium/deps/icu.git" + "@" + "89dcdec16381883782b9cc9cff38e00f047a0f46",
+  # Will change to chromium mirror of WebAssembly before landing.
+  "v8/third_party/wasm":

[Michael Starzinger, 2015/08/18 14:20:40]

Can we for now not pull this dependency? People working on WebAssembly in V8
would need to setup a this dependency (or some sort of symlink) themselves for
now, but the rest of the build-system is ready to build the WebAssembly
prototype without changes. WDYT?

[bradn, 2015/08/18 14:42:44]

Yep, make sense.
Done.

+    "https://github.com/flagxor/v8-native-prototype.git"+ "@" + "7f2d64a953786e25e6466c0dc9641e72e46289f6",
   "v8/buildtools":
     Var("git_url") + "/chromium/buildtools.git" + "@" + "565d04e8741429fb1b4f26d102f2c6c3b849edeb",
   "v8/testing/gtest":
     Var("git_url") + "/external/googletest.git" + "@" + "9855a87157778d39b95eccfb201a9dc90f6d61c6",
   "v8/testing/gmock":
     Var("git_url") + "/external/googlemock.git" + "@" + "0421b6f358139f02e102c9c332ce19a33faf75be",
   "v8/tools/clang":
     Var("git_url") + "/chromium/src/tools/clang.git" + "@" + "5b12e334ec0e571a8e1f68d028dc5427b58c17ec",
 }
 
@@ skipping 84 matching lines @@
     'name': 'clang',
     'pattern': '.',
     'action': ['python', 'v8/tools/clang/scripts/update.py', '--if-needed'],
   },
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     "pattern": ".",
     "action": ["python", "v8/build/gyp_v8"],
   },
 ]