Add a "Simplify Page" option to the print preview dialog

chrome/browser/ui/webui/print_preview/hidden_web_contents.h

+// Copyright (c) 2015 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_BROWSER_UI_WEBUI_PRINT_PREVIEW_HIDDEN_WEB_CONTENTS_H_
+#define CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_HIDDEN_WEB_CONTENTS_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/common/referrer.h"
+#include "ui/gfx/geometry/size.h"
+
+class Profile;
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+class HiddenWebContents : public content::NotificationObserver,
+                          public content::WebContentsObserver,
+                          public base::SupportsWeakPtr<HiddenWebContents> {
+ public:
+  class Observer {
+   public:
+    // Signals that the hidden renderer has stopped running prematurely.
+    virtual void OnFail(HiddenWebContents* contents) = 0;
+
+    // Signals that this hidden renderer has just finished loading.
+    virtual void OnFinishedLoad(HiddenWebContents* contents);
+
+   protected:
+    Observer();
+    virtual ~Observer() = 0;
+  };
+
+  explicit HiddenWebContents(Profile* profile);
+  ~HiddenWebContents() override;
+
+  // All observers of a HiddenWebContents are removed after the OnPrerenderStop
+  // event is sent, so there is no need to call RemoveObserver() in the normal
+  // use case.
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+  // Start rendering the contents in the prerendered state. |size|
+  // indicates the rectangular dimensions that the hidden renderer's page should
+  // be. |session_storage_namespace| indicates the namespace that the hidden
+  // renderer's page should be part of.
+  virtual void StartRendering(
+      const gfx::Size& size,
+      content::SessionStorageNamespace* session_storage_namespace);
+
+  // content::WebContentsObserver implementation.
+  void RenderFrameCreated(content::RenderFrameHost* render_frame_host) override;
+  void DidStopLoading() override;
+  void DocumentLoadedInFrame(
+      content::RenderFrameHost* render_frame_host) override;
+  void DidStartProvisionalLoadForFrame(
+      content::RenderFrameHost* render_frame_host,
+      const GURL& validated_url,
+      bool is_error_page,
+      bool is_iframe_srcdoc) override;
+  void DidFinishLoad(content::RenderFrameHost* render_frame_host,
+                     const GURL& validated_url) override;
+  void DidNavigateMainFrame(
+      const content::LoadCommittedDetails& details,
+      const content::FrameNavigateParams& params) override;
+  void DidGetRedirectForResourceRequest(
+      content::RenderFrameHost* render_frame_host,
+      const content::ResourceRedirectDetails& details) override;
+
+  void RenderProcessGone(base::TerminationStatus status) override;
+
+  // content::NotificationObserver
+  void Observe(int type,
+               const content::NotificationSource& source,
+               const content::NotificationDetails& details) override;
+
+  // The hidden WebContents (may be NULL).
+  content::WebContents* web_contents() {
+    return web_contents_.get();
+  }
+
+  bool rendering_has_been_cancelled() const {
+    return rendering_has_been_cancelled_;
+  }
+
+  // Sets the final status, calls OnDestroy and adds |this| to the
+  // PrerenderManager's pending deletes list.
+  void Destroy();
+
+ protected:
+  // These call out to methods on our Observers, using our observer_list_. Note
+  // that NotifyStop() also clears the observer list.
+  void NotifyStart();
+  void NotifyFail();
+  void NotifyFinishedLoad();
+
+  void ScheduleNotifyFinishLoad();
+
+  content::NotificationRegistrar& notification_registrar() {
+    return notification_registrar_;
+  }
+
+  content::WebContents* CreateWebContents(
+      content::SessionStorageNamespace* session_storage_namespace);
+
+  bool rendering_has_started_;
+
+  // The hidden rendered WebContents; may be null.
+  scoped_ptr<content::WebContents> web_contents_;
+
+  // The session storage namespace id for use in matching. We must save it
+  // rather than get it from the RenderViewHost since in the control group
+  // we won't have a RenderViewHost.
+  int64 session_storage_namespace_id_;
+
+ private:
+  class WebContentsDelegateImpl;
+
+  base::ObserverList<Observer> observer_list_;
+
+  // The profile being used
+  Profile* profile_;
+
+  content::NotificationRegistrar notification_registrar_;
+
+  // True when the main frame has finished loading.
+  bool has_finished_loading_;
+
+  // Tracks whether or not rendering has been cancelled by calling Destroy.
+  // Used solely to prevent double deletion.
+  bool rendering_has_been_cancelled_;
+
+  scoped_ptr<WebContentsDelegateImpl> web_contents_delegate_;
+
+  // The size of the WebView from the launching page.
+  gfx::Size size_;
+
+  DISALLOW_COPY_AND_ASSIGN(HiddenWebContents);
+};
+
+#endif  // CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_HIDDEN_WEB_CONTENTS_H_