Add DEPS.chromium for recursive DEPS tracking.

DEPS.chromium

Index: DEPS.chromium
diff --git a/DEPS.chromium b/DEPS.chromium
new file mode 100644
index 0000000000000000000000000000000000000000..b9d6e9ce85123dd4fb8f5d162a7d535694e3efdd
--- /dev/null
+++ b/DEPS.chromium
@@ -0,0 +1,14 @@
+# This file is used by the Chromium dependency system to pull in V8 dependencies
+# not used by Chromium directly.
+#
+# If you make a change to the dependencies below, the corresponding DEPS file
+# for v8 must also be changed.
+
+vars = {
+  "chromium_url": "https://chromium.googlesource.com",
+}
+
+deps = {
+  "src/v8/test/cctest/traces-arm64":
+    Var("chromium_url") + "/external/git.linaro.org/arm/vixl-simulator-traces.git" + "@" + "6168e7e1eec52c9cb0a62f87f94df0582dc48aa8",
+}