Pull in libFuzzer as a third party dep.

DEPS

Index: DEPS
diff --git a/DEPS b/DEPS
index 1c0cb885db4de805a08ebf6403f979689f358c8f..f5acf37a552ea3ca51d5f962295c944ecb59c5cb 100644
--- a/DEPS
+++ b/DEPS
@@ -101,6 +101,10 @@ vars = {
   # the commit queue can handle CLs rolling catapult
   # and whatever else without interference from each other.
   'catapult_revision': 'f98a1ff33ee6d3575cdbb338b2a2f9fde11e7ee3',
+  # Three lines of non-changing comments so that
+  # the commit queue can handle CLs rolling libFuzzer
+  # and whatever else without interference from each other.
+  'libfuzzer_revision': '7af9c54c44b8ff3beed8456689d04628a3a8a58a',
 }
 
 # Only these hosts are allowed for dependencies in this DEPS file.
@@ -430,6 +434,10 @@ deps_os = {
     # Wireless Display Software. Used on Chrome OS.
     'src/third_party/wds/src':
      Var('chromium_git') + '/external/github.com/01org/wds' + '@' + 'f187dda5fccaad08e168dc6657109325f42c648e',
+
+    # Used for building libFuzzers (only supports Linux).
+    'src/third_party/libFuzzer/src':
+     Var('chromium_git') + '/chromium/llvm-project/llvm/lib/Fuzzer.git' + '@' +  Var('libfuzzer_revision'),
   },
   'android': {
     'src/third_party/android_protobuf/src':