[build] Depend on luci-go via subtree repo

Bug: chromium:754168
Change-Id: Ie3c80b7f566f6738893cc30f26b35b7862eccc6c
Reviewed-on: https://chromium-review.googlesource.com/706996
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48413}

.gitignore

@@ -72,9 +72,7 @@
 /tools/gyp
 /tools/jsfunfuzz/jsfunfuzz
 /tools/jsfunfuzz/jsfunfuzz.tar.gz
-/tools/luci-go/linux64/isolate
-/tools/luci-go/mac64/isolate
-/tools/luci-go/win64/isolate.exe
+/tools/luci-go
 /tools/oom_dump/oom_dump
 /tools/oom_dump/oom_dump.o
 /tools/swarming_client

DEPS

@@ -47,6 +47,8 @@ deps = {
     Var('chromium_url') + '/external/github.com/test262-utils/test262-harness-py.git' + '@' + '0f2acdd882c84cff43b9d60df7574a1901e2cdcd',
   'v8/tools/clang':
     Var('chromium_url') + '/chromium/src/tools/clang.git' + '@' + 'b3169f97cc1a9daa1a9fbae15752588079792098',
+  'v8/tools/luci-go':
+    Var('chromium_url') + '/chromium/src/tools/luci-go.git' + '@' + '9f54aa9fe06499b6bac378ae1f045be2158cf2cc',
   'v8/test/wasm-js':
     Var('chromium_url') + '/external/github.com/WebAssembly/spec.git' + '@' + '4f1d3114157e6459d8a06e7d8fcc8fc90288cd85',
 }

tools/luci-go/linux64/isolate.sha1

-ccdea1387f9f26c2572bf5f2b8d24e8d66a69cf6

tools/luci-go/mac64/isolate.sha1

-71329e82d274b847525f2b6345cb9fb6ddd0fff3

tools/luci-go/win64/isolate.exe.sha1

-ded0dc9247e06fa42b653cce43f461f243ebea8b