Add BoringSSL to DEPS.

DEPS

Index: DEPS
diff --git a/DEPS b/DEPS
index f4c5e64fe6afa74542be36408ccbdb51b8047112..d5e6642c7ac2927f2974593687334815020d0b3f 100644
--- a/DEPS
+++ b/DEPS
@@ -33,6 +33,7 @@ vars = {
   "chromiumos_git": "https://chromium.googlesource.com/chromiumos",
   "pdfium_git": "https://pdfium.googlesource.com",
   "skia_git": "https://skia.googlesource.com",
+  "boringssl_git": "https://boringssl.googlesource.com",
   "swig_revision": "230490",
   "nacl_revision": "13398",
   # After changing nacl_revision, run 'glient sync' and check native_client/DEPS
@@ -81,6 +82,10 @@ vars = {
   # the commit queue can handle CLs rolling openmax_dl
   # and whatever else without interference from each other.
   "openmax_dl_revision": "6483",
+  # Three lines of non-changing comments so that
+  # the commit queue can handle CLs rolling BoringSSL
+  # and whatever else without interference from each other.
+  "boringssl_revision": "facc6ff39e129984d6b03cb16716f449cdacbbdb",
 }
 
 deps = {
@@ -322,6 +327,9 @@ deps = {
 
   "src/third_party/pdfium":
     Var("pdfium_git") + "/pdfium.git@" + Var("pdfium_revision"),
+
+  "src/third_party/boringssl/src":
+    Var("boringssl_git") + "/boringssl.git@" + Var("boringssl_revision"),
 }