Makes GetComponentExtensionResourceManager() thread-safe.

extensions/browser/image_loader.cc

Index: extensions/browser/image_loader.cc
diff --git a/extensions/browser/image_loader.cc b/extensions/browser/image_loader.cc
index cfbe34efebe7962d0d0770d26aa8531fa6f7cad8..61563286e21dfdfdb878dba44999228f8ad39257 100644
--- a/extensions/browser/image_loader.cc
+++ b/extensions/browser/image_loader.cc
@@ -112,9 +112,9 @@ std::vector<SkBitmap> LoadResourceBitmaps(
 
     int resource_id;
     if (extension->location() == Manifest::COMPONENT) {
-      extensions::ComponentExtensionResourceManager* manager =
-          extensions::ExtensionsBrowserClient::Get()->
-          GetComponentExtensionResourceManager();
+      const extensions::ComponentExtensionResourceManager* manager =
+          extensions::ExtensionsBrowserClient::Get()
+              ->GetComponentExtensionResourceManager();
       if (manager && manager->IsComponentExtensionResource(
               extension->path(), it->resource.relative_path(), &resource_id)) {
         LoadResourceOnUIThread(resource_id, &bitmaps[i]);