Option added to protobuf build for import directories

third_party/protobuf/proto_library.gni

Index: third_party/protobuf/proto_library.gni
diff --git a/third_party/protobuf/proto_library.gni b/third_party/protobuf/proto_library.gni
index 7c74e4ef8e422b7ce8d29a5d668c2d44c46a23d7..1c2c62d2f8d20c214ed056de2f863dcaeb3a2ade 100644
--- a/third_party/protobuf/proto_library.gni
+++ b/third_party/protobuf/proto_library.gni
@@ -63,6 +63,10 @@
 #       If adding protobuf library would be required, adds protobuf_full to deps
 #       instead of protobuf_lite.
 #
+#   import_dirs (optional)
+#       A list of extra import directories to be passed to protoc compiler. The

[xyzzyz, 2017/02/10 19:36:03]

As I mentioned in the email, you should add a comment here that explains that
this option is not to be used in Chromium until we figure out the duplicate
symbols issue, along with the link to bug tracking that effort.

[Ramin Halavati, 2017/02/13 06:56:57]

Done.

+#       default case is just proto_in_dir.
+#
 # Parameters for compiling the generated code:
 #
 #   component_build_force_source_set (Default=false)
@@ -277,6 +281,12 @@ template("proto_library") {
       }
     }
 
+    if (defined(invoker.import_dirs)) {
+      foreach(path, invoker.import_dirs) {
+        args += ["--import-dir=" + rebase_path(path, root_build_dir)]
+      }
+    }
+
     # System protoc is not used so it's necessary to build a chromium one.
     inputs = [
       protoc_path,