Implement BrowserPluginPlaceholder.

content/renderer/browser_plugin/browser_plugin_placeholder.h

+// Copyright (c) 2012 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 CONTENT_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_PLACEHOLDER_H_
+#define CONTENT_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_PLACEHOLDER_H_
+#pragma once
+
+#include "base/process.h"
+#include "ipc/ipc_channel_handle.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebString.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebPluginParams.h"
+#include "ui/gfx/size.h"
+#include "webkit/plugins/webview_plugin.h"
+
+namespace content {
+class RenderView;
+}
+
+namespace WebKit {
+class WebPlugin;
+}
+
+// A browser plugin is a plugin container that hosts an out-of-process "guest"
+// RenderView. Loading up a new process, creating a new RenderView, navigating
+// to a given URL, and establishing a guest-to-host channel can take hundreds
+// of milliseconds. Furthermore, a RenderView's associated browser-side
+// WebContents, RenderViewHost, and SiteInstance must be created and accessed on
+// the UI thread of the browser process.
+//
+// To avoid blocking the host RenderView and to avoid introducing the potential
+// for deadlock, the BrowserPluginPlaceholder takes place of the guest
+// RenderView until the guest has established a connection with its host
+// RenderView. This permits loading the guest to happen asynchronously, while
+// the host RenderView is permitted to continue to receive and process events.
+class BrowserPluginPlaceholder: public webkit::WebViewPlugin::Delegate {
+ public:
+  // Creates a new WebViewPlugin with a BrowserPluginPlaceholder as a delegate.
+  static webkit::WebViewPlugin* Create(
+      content::RenderView* render_view,
+      WebKit::WebFrame* frame,
+      const WebKit::WebPluginParams& params);
+
+  static BrowserPluginPlaceholder* FromID(int id);
+
+  void RegisterPlaceholder(int id, BrowserPluginPlaceholder* placeholder);
+  void UnregisterPlaceholder(int id);
+
+  int GetID() { return id_; }
+
+  webkit::WebViewPlugin* plugin() { return plugin_; }
+
+  const WebKit::WebPluginParams& plugin_params() const;
+
+  void GuestReady(base::ProcessHandle process_handle,
+                  const IPC::ChannelHandle& channel_handle);
+
+  content::RenderView* render_view() { return render_view_; }
+
+ private:
+  BrowserPluginPlaceholder(content::RenderView* render_view,
+                           WebKit::WebFrame* frame,
+                           const WebKit::WebPluginParams& params,
+                           const std::string& html_data);
+  virtual ~BrowserPluginPlaceholder();
+
+  // Grabs the width, height, and source URL of the browser plugin
+  // from the element's attributes. If not found, it uses the defaults
+  // specified here as parameters.
+  void GetPluginParameters(int default_width, int default_height,
+                           const std::string& default_src);
+  // Replace this placeholder with the real browser plugin.
+  void LoadGuest(WebKit::WebPlugin* new_plugin);
+
+  virtual void BindWebFrame(WebKit::WebFrame* frame) OVERRIDE { }
+  virtual void WillDestroyPlugin() OVERRIDE;
+  virtual void ShowContextMenu(const WebKit::WebMouseEvent&) OVERRIDE { }
+
+  content::RenderView* render_view_;
+  WebKit::WebPluginParams plugin_params_;
+  webkit::WebViewPlugin* plugin_;
+  int id_;
+  gfx::Size size_;
+  std::string src_;
+
+  DISALLOW_COPY_AND_ASSIGN(BrowserPluginPlaceholder);
+};
+
+#endif  // CONTNET_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_PLACEHOLDER_H_