Strip comments and whitespace from javascript resources

third_party/closure_compiler/closure_args.gni

Index: third_party/closure_compiler/closure_args.gni
diff --git a/third_party/closure_compiler/closure_args.gni b/third_party/closure_compiler/closure_args.gni
index 425165b2c073e6106403de38a57bcc96ee8a7ea6..d6960e99d299f3c26bee40d4ddf5bb3f703c5d63 100644
--- a/third_party/closure_compiler/closure_args.gni
+++ b/third_party/closure_compiler/closure_args.gni
@@ -3,9 +3,9 @@
 # found in the LICENSE file.
 
 # GYP version: third_party/closure_compiler/closure_args.gypi
-default_closure_args = [
-  "compilation_level=SIMPLE_OPTIMIZATIONS",
 
+# Args for all uses of the closure compiler
+common_closure_args = [
   "extra_annotation_name=attribute",
   "extra_annotation_name=demo",
   "extra_annotation_name=element",
@@ -15,6 +15,13 @@ default_closure_args = [
   "extra_annotation_name=status",
   "extra_annotation_name=submodule",
 
+  "source_map_format=V3",
+]
+
+# Additional closure args for performing full checks.
+checking_closure_args = [
+  "compilation_level=SIMPLE_OPTIMIZATIONS",
+
   "jscomp_error=accessControls",
   "jscomp_error=ambiguousFunctionDecl",
   "jscomp_error=checkTypes",
@@ -38,10 +45,19 @@ default_closure_args = [
   "language_out=ECMASCRIPT5_STRICT",
 
   "polymer_pass",
+]
 
-  "source_map_format=V3",
+# Additional closure arguments for minifying
+minifying_closure_args = [
+  "compilation_level=WHITESPACE_ONLY",
+
+  "language_in=ECMASCRIPT6",
+  "language_out=ECMASCRIPT6",
 ]
 
+# For compatibility with old uses.
+default_closure_args = common_closure_args + checking_closure_args
+
 default_disabled_closure_args = [
   "jscomp_off=duplicate",
   "jscomp_off=misplacedTypeAnnotation",