Enhance chrome.app.window API with window background color

extensions/browser/api/app_window/app_window_api.cc

Index: extensions/browser/api/app_window/app_window_api.cc
diff --git a/extensions/browser/api/app_window/app_window_api.cc b/extensions/browser/api/app_window/app_window_api.cc
index 10d91fbdd1084e1c08d2d20b1973ab51464980ab..83608c30451eaa03709c979161f34b92a13f19c7 100644
--- a/extensions/browser/api/app_window/app_window_api.cc
+++ b/extensions/browser/api/app_window/app_window_api.cc
@@ -298,6 +298,14 @@ bool AppWindowCreateFunction::RunAsync() {
 #endif
     }
 
+    if (options->background_color.get()) {
+      if (!image_util::ParseHexColorString(*options->background_color,
+                                           &create_params.background_color)) {
+        error_ = app_window_constants::kInvalidColorSpecification;
+        return false;
+      }
+    }
+
     if (options->hidden.get())
       create_params.hidden = *options->hidden;