Add support for distilling current WebContents

chrome/browser/dom_distiller/tab_utils.cc

+// Copyright 2014 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.
+
+#include "chrome/browser/dom_distiller/tab_utils.h"
+
+#include "base/message_loop/message_loop.h"
+#include "chrome/browser/dom_distiller/dom_distiller_service_factory.h"
+#include "chrome/browser/ui/tab_contents/core_tab_helper.h"
+#include "chrome/browser/ui/tab_contents/core_tab_helper_delegate.h"
+#include "chrome/common/url_constants.h"
+#include "components/dom_distiller/content/distiller_page_web_contents.h"
+#include "components/dom_distiller/core/distiller_page.h"
+#include "components/dom_distiller/core/dom_distiller_service.h"
+#include "components/dom_distiller/core/task_tracker.h"
+#include "components/dom_distiller/core/url_utils.h"
+#include "content/public/browser/browser_context.h"
+#include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_observer.h"
+
+namespace dom_distiller {
+
+namespace tab_utils {
+
+// An no-op ViewRequestDelegate which holds a ViewerHandle and deletes itself
+// after the WebContents navigates or goes away. This class is a band-aid to
+// keep a TaskTracker around until the distillation starts from the viewer.
+class SelfDeletingRequestDelegate : public ViewRequestDelegate,
+                                    public content::WebContentsObserver {
+ public:
+  explicit SelfDeletingRequestDelegate(content::WebContents* web_contents);
+  virtual ~SelfDeletingRequestDelegate();
+
+  // ViewRequestDelegate implementation.
+  virtual void OnArticleReady(
+      const DistilledArticleProto* article_proto) OVERRIDE;
+  virtual void OnArticleUpdated(
+      ArticleDistillationUpdate article_update) OVERRIDE;
+
+  // content::WebContentsObserver implementation.
+  virtual void DidNavigateMainFrame(
+      const content::LoadCommittedDetails& details,
+      const content::FrameNavigateParams& params) OVERRIDE;
+  virtual void RenderProcessGone(base::TerminationStatus status) OVERRIDE;
+  virtual void WebContentsDestroyed() OVERRIDE;
+
+  // Takes ownership of the ViewerHandle to keep distillation alive until |this|
+  // is deleted.
+  void TakeViewerHandle(scoped_ptr<ViewerHandle> viewer_handle);
+
+ private:
+  // The handle to the view request towards the DomDistillerService. It
+  // needs to be kept around to ensure the distillation request finishes.
+  scoped_ptr<ViewerHandle> viewer_handle_;
+
+  // The WebContents this class is tracking.
+  content::WebContents* web_contents_;
+};
+
+void SelfDeletingRequestDelegate::DidNavigateMainFrame(
+    const content::LoadCommittedDetails& details,
+    const content::FrameNavigateParams& params) {
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+}
+
+void SelfDeletingRequestDelegate::RenderProcessGone(
+    base::TerminationStatus status) {
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+}
+
+void SelfDeletingRequestDelegate::WebContentsDestroyed() {
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+}
+
+SelfDeletingRequestDelegate::SelfDeletingRequestDelegate(
+    content::WebContents* web_contents)
+    : web_contents_(web_contents) {
+  content::WebContentsObserver::Observe(web_contents_);
+}
+
+SelfDeletingRequestDelegate::~SelfDeletingRequestDelegate() {
+  content::WebContentsObserver::Observe(NULL);
+}
+
+void SelfDeletingRequestDelegate::OnArticleReady(
+    const DistilledArticleProto* article_proto) {
+}
+
+void SelfDeletingRequestDelegate::OnArticleUpdated(
+    ArticleDistillationUpdate article_update) {
+}
+
+void SelfDeletingRequestDelegate::TakeViewerHandle(
+    scoped_ptr<ViewerHandle> viewer_handle) {
+  viewer_handle_ = viewer_handle.Pass();
+}
+
+// Start loading the viewer URL of the current page in |web_contents|.
+void StartNavigationToDistillerViewer(content::WebContents* web_contents,
+                                      const GURL& url) {
+  GURL viewer_url =
+      url_utils::GetDistillerViewUrlFromUrl(chrome::kDomDistillerScheme, url);
+  content::NavigationController::LoadURLParams params(viewer_url);
+  web_contents->GetController().LoadURLWithParams(params);
+}
+
+void StartDistillation(content::WebContents* web_contents) {
+  // Start distillation using |web_contents|, and ensure ViewerHandle stays
+  // around until the viewer requests distillation.
+  SelfDeletingRequestDelegate* view_request_delegate =
+      new SelfDeletingRequestDelegate(web_contents);
+  scoped_ptr<content::WebContents> old_web_contents_sptr(web_contents);
+  scoped_ptr<SourcePageHandleWebContents> source_page_handle(
+      new SourcePageHandleWebContents(old_web_contents_sptr.Pass()));
+  DomDistillerService* dom_distiller_service =
+      DomDistillerServiceFactory::GetForBrowserContext(
+          web_contents->GetBrowserContext());
+  scoped_ptr<DistillerPage> distiller_page =
+      dom_distiller_service->CreateDefaultDistillerPageWithHandle(
+                                 source_page_handle.PassAs<SourcePageHandle>())
+          .Pass();
+
+  const GURL& last_committed_url = web_contents->GetLastCommittedURL();
+  scoped_ptr<ViewerHandle> viewer_handle = dom_distiller_service->ViewUrl(
+      view_request_delegate, distiller_page.Pass(), last_committed_url);
+  view_request_delegate->TakeViewerHandle(viewer_handle.Pass());
+}
+
+void DistillCurrentPageAndView(content::WebContents* old_web_contents) {
+  DCHECK(old_web_contents);
+  // Create new WebContents.
+  content::WebContents::CreateParams create_params(
+      old_web_contents->GetBrowserContext());
+  content::WebContents* new_web_contents =
+      content::WebContents::Create(create_params);
+  DCHECK(new_web_contents);
+
+  // Copy all navigation state from the old WebContents to the new one.
+  new_web_contents->GetController().CopyStateFrom(
+      old_web_contents->GetController());
+
+  CoreTabHelper::FromWebContents(old_web_contents)->delegate()->SwapTabContents(
+      old_web_contents, new_web_contents, false, false);
+
+  StartNavigationToDistillerViewer(new_web_contents,
+                                   old_web_contents->GetLastCommittedURL());
+  StartDistillation(old_web_contents);
+}
+
+}  // namespace tab_utils
+
+}  // namespace dom_distiller