Show a new placeholder for PDF's when plugins are disabled.

chrome/renderer/plugins/pdf_plugin_placeholder.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_RENDERER_PLUGINS_PDF_PLUGIN_PLACEHOLDER_H_
+#define CHROME_RENDERER_PLUGINS_PDF_PLUGIN_PLACEHOLDER_H_
+
+#include "components/plugins/renderer/plugin_placeholder.h"
+
+class PDFPluginPlaceholder final : public plugins::PluginPlaceholderBase,

[tommycli, 2017/06/29 23:31:41]

Add a comment as to the purpose of the class. And in that comment probably add a
TODO for you to flesh out the class more.

[amberwon, 2017/06/30 01:18:53]

Done.

+                                   public gin::Wrappable<PDFPluginPlaceholder> {
+ public:
+  static gin::WrapperInfo kWrapperInfo;
+  static PDFPluginPlaceholder* CreateBlockedPlugin(

[tommycli, 2017/06/29 23:31:41]

Should probably be CreatePDFPlaceholder ... and there's no reason to take the
template_id as a parameter, since it will always be fixed.

One more nit: one space above this method plz

[amberwon, 2017/06/30 01:18:53]

Done.

+      content::RenderFrame* render_frame,
+      const blink::WebPluginParams& params,
+      int template_id);
+
+ private:
+  PDFPluginPlaceholder(content::RenderFrame* render_frame,
+                       const blink::WebPluginParams& params,
+                       const std::string& html_data);
+  ~PDFPluginPlaceholder() override;
+
+  // WebViewPlugin::Delegate methods:
+  v8::Local<v8::Value> GetV8Handle(v8::Isolate* isolate) final;
+};
+
+#endif  // CHROME_RENDERER_PLUGINS_PDF_PLUGIN_PLACEHOLDER_H_