Revert of Plugins: Remove Shadow DOM Plugin Placeholder

content/public/renderer/content_renderer_client.h

Index: content/public/renderer/content_renderer_client.h
diff --git a/content/public/renderer/content_renderer_client.h b/content/public/renderer/content_renderer_client.h
index 09765e19dad4d98ed5a488a40f87faffbfd7022f..b1b0527a106a476a5b00e1bd789f71f7c4dbae0d 100644
--- a/content/public/renderer/content_renderer_client.h
+++ b/content/public/renderer/content_renderer_client.h
@@ -39,6 +39,7 @@
 class WebMediaStreamCenterClient;
 class WebPlugin;
 class WebPluginContainer;
+class WebPluginPlaceholder;
 class WebPrescientNetworking;
 class WebRTCPeerConnectionHandler;
 class WebRTCPeerConnectionHandlerClient;
@@ -90,6 +91,14 @@
   // Returns the bitmap to show when a <webview> guest has crashed, or NULL for
   // none.
   virtual SkBitmap* GetSadWebViewBitmap();
+
+  // Allows the embedder to create a plugin placeholder instead of a plugin.
+  // Called before OverrideCreatePlugin. May return null to decline to provide
+  // a plugin placeholder.
+  virtual scoped_ptr<blink::WebPluginPlaceholder> CreatePluginPlaceholder(
+      RenderFrame* render_frame,
+      blink::WebLocalFrame* frame,
+      const blink::WebPluginParams& params);
 
   // Allows the embedder to override creating a plugin. If it returns true, then
   // |plugin| will contain the created plugin, although it could be NULL. If it