Add dependency on buildtools repo

Currently, this adds checkdeps, in the future, this will be the place
where clang-format and gn lives.

BUG=none
R=machenbach@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/308353002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21636 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

.DEPS.git

@@ -13,6 +13,8 @@ vars = {
 deps = {
     'v8/build/gyp':
         Var('git_url') + '/external/gyp.git@a3e2a5caf24a1e0a45401e09ad131210bf16b852',
+    'v8/buildtools':
+        Var('git_url') + '/chromium/buildtools.git@83ed7189066fd9b4b9ea15ffc2d4ab6d2da62571',
     'v8/third_party/icu':
         Var('git_url') + '/chromium/deps/icu46.git@7a1ec88f69e25b3efcf76196d07f7815255db025',
 }

DEPS

@@ -4,6 +4,8 @@
 
 vars = {
   "chromium_trunk": "https://src.chromium.org/svn/trunk",
+
+  "buildtools_revision": "83ed7189066fd9b4b9ea15ffc2d4ab6d2da62571",
 }
 
 deps = {
@@ -13,6 +15,10 @@ deps = {
 
   "v8/third_party/icu":
     Var("chromium_trunk") + "/deps/third_party/icu46@258359",
+
+  "v8/buildtools":
+    "https://chromium.googlesource.com/chromium/buildtools.git@" +
+    Var("buildtools_revision"),
 }
 
 deps_os = {

Makefile

@@ -468,3 +468,8 @@ dependencies:
 	svn checkout --force \
 	    https://src.chromium.org/chrome/trunk/deps/third_party/icu46 \
 	    third_party/icu --revision 258359
+	( cd buildtools || \
+	  git clone https://chromium.googlesource.com/chromium/buildtools.git; \
+	  cd buildtools; \
+	  git fetch origin; \
+	  git checkout 83ed7189066fd9b4b9ea15ffc2d4ab6d2da62571 )