Add some closureised JS bindings for DevTools for use by headless embedder

third_party/closure_compiler/compile_js.gni

Index: third_party/closure_compiler/compile_js.gni
diff --git a/third_party/closure_compiler/compile_js.gni b/third_party/closure_compiler/compile_js.gni
index 958ac1bc9b7c897d2d3af141bd79b371203cb2f2..329bb75f0d03fdaacbf5f2ecbfd37f3472a9dccb 100644
--- a/third_party/closure_compiler/compile_js.gni
+++ b/third_party/closure_compiler/compile_js.gni
@@ -17,6 +17,10 @@ compiler_path = "$script_path/compiler/compiler.jar"
 #   deps:
 #     List of js_library targets to depend on
 #
+#   extra_deps:
+#     List of any other rules to depend on. E.g. a rule that generates js source
+#     files
+#
 # Example:
 #   js_library("apple_tree") {
 #     sources = ["tree_main.js"]
@@ -36,6 +40,7 @@ template("js_library") {
                            [
                              "sources",
                              "deps",
+                             "extra_deps",
                            ])
     output_file = "$target_gen_dir/$target_name.js_library"
     outputs = [
@@ -55,6 +60,12 @@ template("js_library") {
         args += [ rebase_path(dep_output_path, root_build_dir) ]
       }
     }
+    if (defined(extra_deps)) {
+      if (!defined(deps)) {
+        deps = []
+      }
+      deps += extra_deps
+    }
   }
 }