Use a placeholder instead of the default plugin for missing plug-ins on Mac and Linux.

content/browser/plugin_service.cc

Index: content/browser/plugin_service.cc
diff --git a/content/browser/plugin_service.cc b/content/browser/plugin_service.cc
index 4f0aabfafac2da9b2fb793631b335ca24fa4af85..2c74921ac9332506a1cc1d6dbd78b88b1ab9082f 100644
--- a/content/browser/plugin_service.cc
+++ b/content/browser/plugin_service.cc
@@ -62,6 +62,12 @@ static void GetPluginsForGroupsCallback(
   callback.Run(groups);
 }
 
+static void GetPluginsAndIgnoreCallback(
+    const base::Closure& callback,
+    const std::vector<webkit::WebPluginInfo>& plugins) {
+  callback.Run();
+}
+
 // Callback set on the PluginList to assert that plugin loading happens on the
 // correct thread.
 void WillLoadPluginsCallback() {
@@ -482,6 +488,18 @@ void PluginService::FinishOpenChannelToPlugin(
   }
 }
 
+bool PluginService::GetPluginInfoArray(
+    const GURL& url,
+    const std::string& mime_type,
+    bool allow_wildcard,
+    std::vector<webkit::WebPluginInfo>* plugins,
+    std::vector<std::string>* actual_mime_types) {
+  bool use_stale = false;
+  webkit::npapi::PluginList::Singleton()->GetPluginInfoArray(
+      url, mime_type, allow_wildcard, &use_stale, plugins, actual_mime_types);
+  return use_stale;
+}
+
 bool PluginService::GetPluginInfo(int render_process_id,
                                   int render_view_id,
                                   const content::ResourceContext& context,
@@ -568,6 +586,10 @@ void PluginService::GetPluginsInternal(
       base::Bind(&RunGetPluginsCallback, callback, plugins));
 }
 
+void PluginService::EnsurePluginsLoaded(const base::Closure& callback) {
+  GetPlugins(base::Bind(&GetPluginsAndIgnoreCallback, callback));
+}
+
 void PluginService::OnWaitableEventSignaled(
     base::WaitableEvent* waitable_event) {
 #if defined(OS_WIN)