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

third_party/closure_compiler/compile_js.gni

 # Copyright 2017 The Chromium Authors.  All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//third_party/closure_compiler/closure_args.gni")
 
 script_path = "//third_party/closure_compiler"
 compiler_path = "$script_path/compiler/compiler.jar"
 
 # Defines a target that creates an ordering for .js files to be used by
 # js_binary to compile.
 #
 # Variables:
 #   sources:
 #     List of Javascript files to include in the library
 #
 #   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"]
 #     deps = [
 #       ":branch",
 #       ":trunk",
 #       ":root",
 #     ]
 #   }
 
 template("js_library") {
   assert(defined(invoker.sources) || defined(invoker.deps),
          "Need sources or deps in $target_name for js_library")
   action(target_name) {
     script = "$script_path/js_library.py"
     forward_variables_from(invoker,
                            [
                              "sources",
                              "deps",
+                             "extra_deps",
                            ])
     output_file = "$target_gen_dir/$target_name.js_library"
     outputs = [
       output_file,
     ]
     args = [ "--output" ] + [ rebase_path(output_file, root_build_dir) ]
     if (defined(sources)) {
       args += [ "--sources" ] + rebase_path(sources, root_build_dir)
     }
     if (defined(deps)) {
       args += [ "--deps" ]
       foreach(dep, deps) {
         # Get the output path for each dep
         dep_gen_dir = get_label_info(dep, "target_gen_dir")
         dep_name = get_label_info(dep, "name")
         dep_output_path = "$dep_gen_dir/$dep_name.js_library"
         args += [ rebase_path(dep_output_path, root_build_dir) ]
       }
     }
+    if (defined(extra_deps)) {
+      if (!defined(deps)) {
+        deps = []
+      }
+      deps += extra_deps
+    }
   }
 }
 
 # Defines a target that compiles javascript files using the Closure compiler.
 # This will produce a minified javascript output file. Additional checks and
 # optimizations can be configured using the closure_flags attribute.
 #
 # Variables:
 #   sources:
 #     List of .js files to compile
@@ skipping 88 matching lines @@
     if (defined(closure_flags)) {
       args += closure_flags
     }
     if (defined(externs_list)) {
       args += [ "--externs" ]
       args += rebase_path(externs_list, root_build_dir)
       sources += externs_list
     }
   }
 }