Strip comments and whitespace from javascript resources

tools/grit/grit_rule.gni

Index: tools/grit/grit_rule.gni
diff --git a/tools/grit/grit_rule.gni b/tools/grit/grit_rule.gni
index b77a24d5e6fb3f2f429bb47c8f71fcea2941774e..650c7e0085065564e8dcba0f07d97f90cd672769 100644
--- a/tools/grit/grit_rule.gni
+++ b/tools/grit/grit_rule.gni
@@ -82,6 +82,7 @@ import("//build/config/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
+import("//third_party/closure_compiler/closure_args.gni")
 
 declare_args() {
   # Enables used resource whitelist generation.
@@ -300,6 +301,11 @@ if (mac_views_browser) {
   ]
 }
 
+# TODO(aberent): Enable for other platforms once the build machines have
+#                Java on them (and hence can run the closure compiler).
+_strip_resource_files = is_android
+_js_minifier = "//third_party/closure_compiler/js_minify.py"
+
 grit_resource_id_file = "//tools/gritsettings/resource_ids"
 grit_info_script = "//tools/grit/grit_info.py"
 
@@ -441,6 +447,20 @@ template("grit") {
 
     args += grit_flags + assert_files_flags
 
+    if (_strip_resource_files) {
+      js_minifier_command = rebase_path(_js_minifier)
+      js_minifier_command = "$js_minifier_command --closure_args"
+      foreach(closure_arg,
+              common_closure_args + default_disabled_closure_args) {
+        js_minifier_command = "$js_minifier_command $closure_arg"
+      }
+      args += [
+        "--js-minifier",
+        js_minifier_command,
+      ]
+      inputs += [ _js_minifier ]
+    }
+
     if (defined(invoker.visibility)) {
       # This needs to include both what the invoker specified (since they
       # probably include generated headers from this target), as well as the