Remove enable_polymer_v08 flag from build

ui/resources/BUILD.gn

Index: ui/resources/BUILD.gn
diff --git a/ui/resources/BUILD.gn b/ui/resources/BUILD.gn
index b81dd3a723527c757c07308bef6448fee7e4eef6..b73e0db9c4a97c60d44f005305a693bd7d931841 100644
--- a/ui/resources/BUILD.gn
+++ b/ui/resources/BUILD.gn
@@ -5,11 +5,6 @@
 import("//tools/grit/grit_rule.gni")
 import("//tools/grit/repack.gni")
 
-declare_args() {
-  # Enable to include Polymer 0.8 in the binary.
-  enable_polymer_v08 = false
-}
-
 # GYP version: ui/resources/ui_resources.gyp:ui_resources
 group("resources") {
   deps = [
@@ -40,11 +35,6 @@ grit("ui_unscaled_resources_grd") {
   ]
 }
 
-webui_grit_defines = []
-if (enable_polymer_v08) {
-  webui_grit_defines += [ "enable_polymer_v08" ]
-}
-
 grit("webui_resources_grd") {
   source = "../webui/resources/webui_resources.grd"
   outputs = [
@@ -53,7 +43,6 @@ grit("webui_resources_grd") {
     "grit/webui_resources_map.h",
     "webui_resources.pak",
   ]
-  defines = webui_grit_defines
 }
 
 if (!is_mac) {