Instant: Use only one hidden WebContents per profile.

chrome/browser/instant/instant_loader.h

-// Copyright 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 CHROME_BROWSER_INSTANT_INSTANT_LOADER_H_
-#define CHROME_BROWSER_INSTANT_INSTANT_LOADER_H_
-
-#include "base/basictypes.h"
-#include "base/callback.h"
-#include "base/compiler_specific.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/timer.h"
-#include "chrome/browser/ui/tab_contents/core_tab_helper_delegate.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
-#include "content/public/browser/web_contents_delegate.h"
-
-class GURL;
-class Profile;
-
-namespace content {
-struct OpenURLParams;
-class WebContents;
-}
-
-// InstantLoader is used to create and maintain a WebContents where we can
-// preload a page into. It is used by InstantOverlay and InstantNTP to
-// preload an Instant page.
-class InstantLoader : public content::NotificationObserver,
-                      public content::WebContentsDelegate,
-                      public CoreTabHelperDelegate {
- public:
-  // InstantLoader calls these methods on its delegate in response to certain
-  // changes in the underlying contents.
-  class Delegate {
-   public:
-    // Called after someone has swapped in a different WebContents for ours.
-    virtual void OnSwappedContents() = 0;
-
-    // Called when the underlying contents receive focus.
-    virtual void OnFocus() = 0;
-
-    // Called when the mouse pointer is down.
-    virtual void OnMouseDown() = 0;
-
-    // Called when the mouse pointer is released (or a drag event ends).
-    virtual void OnMouseUp() = 0;
-
-    // Called to open a URL using the underlying contents (see
-    // WebContentsDelegate::OpenURLFromTab). The Delegate should return the
-    // WebContents the URL is opened in, or NULL if the URL wasn't opened
-    // immediately.
-    virtual content::WebContents* OpenURLFromTab(
-        content::WebContents* source,
-        const content::OpenURLParams& params) = 0;
-
-   protected:
-    ~Delegate();
-  };
-
-  explicit InstantLoader(Delegate* delegate);
-  virtual ~InstantLoader();
-
-  // Creates a new WebContents in the context of |profile| that will be used to
-  // load |instant_url|. The page is not actually loaded until Load() is
-  // called. Uses |active_contents|, if non-NULL, to initialize the size of the
-  // new contents. |on_stale_callback| will be called after kStalePageTimeoutMS
-  // has elapsed after Load() being called.
-  void Init(const GURL& instant_url,
-            Profile* profile,
-            const content::WebContents* active_contents,
-            const base::Closure& on_stale_callback);
-
-  // Loads |instant_url_| in |contents_|.
-  void Load();
-
-  // Returns the contents currently held. May be NULL.
-  content::WebContents* contents() const { return contents_.get(); }
-
-  // Replaces the contents held with |contents|. Any existing contents is
-  // deleted. The expiration timer is not restarted.
-  void SetContents(scoped_ptr<content::WebContents> contents);
-
-  // Releases the contents currently held. Must only be called if contents() is
-  // not NULL.
-  scoped_ptr<content::WebContents> ReleaseContents() WARN_UNUSED_RESULT;
-
- private:
-  // Overridden from content::NotificationObserver:
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
-
-  // Overridden from CoreTabHelperDelegate:
-  virtual void SwapTabContents(content::WebContents* old_contents,
-                               content::WebContents* new_contents) OVERRIDE;
-
-  // Overridden from content::WebContentsDelegate:
-  virtual bool ShouldSuppressDialogs() OVERRIDE;
-  virtual bool ShouldFocusPageAfterCrash() OVERRIDE;
-  virtual void LostCapture() OVERRIDE;
-  virtual void WebContentsFocused(content::WebContents* contents) OVERRIDE;
-  virtual bool CanDownload(content::RenderViewHost* render_view_host,
-                           int request_id,
-                           const std::string& request_method) OVERRIDE;
-  virtual void HandleMouseDown() OVERRIDE;
-  virtual void HandleMouseUp() OVERRIDE;
-  virtual void HandlePointerActivate() OVERRIDE;
-  virtual void HandleGestureEnd() OVERRIDE;
-  virtual void DragEnded() OVERRIDE;
-  virtual bool OnGoToEntryOffset(int offset) OVERRIDE;
-  virtual content::WebContents* OpenURLFromTab(
-      content::WebContents* source,
-      const content::OpenURLParams& params) OVERRIDE;
-
-  Delegate* const delegate_;
-  scoped_ptr<content::WebContents> contents_;
-
-  // The URL we will be loading.
-  GURL instant_url_;
-
-  // Called when |stale_page_timer_| fires.
-  base::Closure on_stale_callback_;
-
-  // Used to mark when the page is stale.
-  base::Timer stale_page_timer_;
-
-  // Used to get notifications about renderers.
-  content::NotificationRegistrar registrar_;
-
-  DISALLOW_COPY_AND_ASSIGN(InstantLoader);
-};
-
-#endif  // CHROME_BROWSER_INSTANT_INSTANT_LOADER_H_