ThumbnailTabHelper: Capture thumbnail when page load finishes

chrome/browser/thumbnails/thumbnail_tab_helper.cc

 // 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.
 
 #include "chrome/browser/thumbnails/thumbnail_tab_helper.h"
 
+#include "base/feature_list.h"
 #include "build/build_config.h"
-#include "chrome/browser/browser_process.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/thumbnails/thumbnail_service.h"
 #include "chrome/browser/thumbnails/thumbnail_service_factory.h"
 #include "chrome/browser/thumbnails/thumbnailing_algorithm.h"
-#include "chrome/browser/thumbnails/thumbnailing_context.h"
+#include "chrome/common/chrome_features.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/render_widget_host_view.h"
-#include "ui/gfx/color_utils.h"
 #include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/scrollbar_size.h"
-#include "ui/gfx/skbitmap_operations.h"
-
-#if defined(OS_WIN)
-#include "base/win/windows_version.h"
-#endif
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(ThumbnailTabHelper);
 
 class SkBitmap;
 
 // Overview
 // --------
 // This class provides a service for updating thumbnails to be used in
 // "Most visited" section of the new tab page. The service can be started
-// by StartThumbnailing(). The current algorithm of the service is as
+// by UpdateThumbnailIfNecessary(). The current algorithm of the service is as
 // simple as follows:
 //
 //    When a renderer is about to be hidden (this usually occurs when the

[Lei Zhang, 2017/05/05 21:32:01]

Can you mention the new behavior in a separate paragraph here?

[Marc Treib, 2017/05/08 08:30:58]

Done.

 //    current tab is closed or another tab is clicked), update the
 //    thumbnail for the tab rendered by the renderer, if needed. The
 //    heuristics to judge whether or not to update the thumbnail is
 //    implemented in ShouldUpdateThumbnail().
 
 using content::RenderViewHost;
 using content::RenderWidgetHost;
 using content::WebContents;
 
-using thumbnails::ClipResult;
 using thumbnails::ThumbnailingContext;
 using thumbnails::ThumbnailingAlgorithm;
 
 ThumbnailTabHelper::ThumbnailTabHelper(content::WebContents* contents)
     : content::WebContentsObserver(contents),
+      capture_on_load_finished_(base::FeatureList::IsEnabled(
+          features::kCaptureThumbnailOnLoadFinished)),
       load_interrupted_(false),
       weak_factory_(this) {
   // Even though we deal in RenderWidgetHosts, we only care about its
   // subclass, RenderViewHost when it is in a tab. We don't make thumbnails
   // for RenderViewHosts that aren't in tabs, or RenderWidgetHosts that
   // aren't views like select popups.
   registrar_.Add(this,
                  content::NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED,
                  content::Source<WebContents>(contents));
 }
@@ skipping 12 matching lines @@
     case content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED:
       if (!*content::Details<bool>(details).ptr())
         WidgetHidden(content::Source<RenderWidgetHost>(source).ptr());
       break;
 
     default:
       NOTREACHED() << "Unexpected notification type: " << type;
   }
 }
 
-void ThumbnailTabHelper::RenderViewDeleted(
-    content::RenderViewHost* render_view_host) {
+void ThumbnailTabHelper::RenderViewDeleted(RenderViewHost* render_view_host) {
   bool registered = registrar_.IsRegistered(
       this, content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
       content::Source<RenderWidgetHost>(render_view_host->GetWidget()));
   if (registered) {
     registrar_.Remove(
         this, content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
         content::Source<RenderWidgetHost>(render_view_host->GetWidget()));
   }
 }
 
 void ThumbnailTabHelper::DidStartLoading() {
   load_interrupted_ = false;
 }
 
+void ThumbnailTabHelper::DidStopLoading() {
+  if (capture_on_load_finished_) {
+    UpdateThumbnailIfNecessary();
+  }
+}
+
 void ThumbnailTabHelper::NavigationStopped() {
   // This function gets called when the page loading is interrupted by the
   // stop button.
   load_interrupted_ = true;
 }
 
 void ThumbnailTabHelper::UpdateThumbnailIfNecessary() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   // Ignore thumbnail update requests if one is already in progress.
   if (thumbnailing_context_) {
@@ skipping 41 matching lines @@
   gfx::Rect copy_rect = gfx::Rect(view->GetViewBounds().size());
   // Clip the pixels that will commonly hold a scrollbar, which looks bad in
   // thumbnails.
   int scrollbar_size = gfx::scrollbar_size();
   copy_rect.Inset(0, 0, scrollbar_size, scrollbar_size);
 
   if (copy_rect.IsEmpty()) {
     return;
   }
 
-  scoped_refptr<thumbnails::ThumbnailingAlgorithm> algorithm(
+  scoped_refptr<ThumbnailingAlgorithm> algorithm(
       thumbnail_service->GetThumbnailingAlgorithm());
 
   thumbnailing_context_ = new ThumbnailingContext(web_contents(),
                                                   thumbnail_service.get(),
                                                   load_interrupted_);
 
   ui::ScaleFactor scale_factor =
       ui::GetSupportedScaleFactor(
           ui::GetScaleFactorForNativeView(view->GetNativeView()));
   thumbnailing_context_->clip_result = algorithm->GetCanvasCopyInfo(
       copy_rect.size(),
       scale_factor,
       &copy_rect,
       &thumbnailing_context_->requested_copy_size);
   view->CopyFromSurface(copy_rect, thumbnailing_context_->requested_copy_size,
                         base::Bind(&ThumbnailTabHelper::ProcessCapturedBitmap,
                                    weak_factory_.GetWeakPtr(), algorithm),
                         kN32_SkColorType);
 }
 
 void ThumbnailTabHelper::ProcessCapturedBitmap(
-    scoped_refptr<thumbnails::ThumbnailingAlgorithm> algorithm,
+    scoped_refptr<ThumbnailingAlgorithm> algorithm,
     const SkBitmap& bitmap,
     content::ReadbackResponse response) {
   if (response == content::READBACK_SUCCESS) {
     // On success, we must be on the UI thread.
     DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
     algorithm->ProcessBitmap(thumbnailing_context_,
                              base::Bind(&ThumbnailTabHelper::UpdateThumbnail,
                                         weak_factory_.GetWeakPtr()),
                              bitmap);
   } else {
     // On failure because of shutdown we are not on the UI thread, so ensure
     // that cleanup happens on that thread.
     content::BrowserThread::PostTask(
         content::BrowserThread::UI,
         FROM_HERE,
         base::Bind(&ThumbnailTabHelper::CleanUpFromThumbnailGeneration,
                    weak_factory_.GetWeakPtr()));
   }
 }
 
 void ThumbnailTabHelper::CleanUpFromThumbnailGeneration() {
   // Make a note that thumbnail generation is complete.
   thumbnailing_context_ = nullptr;
 }
 
-void ThumbnailTabHelper::UpdateThumbnail(
-    const thumbnails::ThumbnailingContext& context,
-    const SkBitmap& thumbnail) {
+void ThumbnailTabHelper::UpdateThumbnail(const ThumbnailingContext& context,
+                                         const SkBitmap& thumbnail) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   // Feed the constructed thumbnail to the thumbnail service.
   gfx::Image image = gfx::Image::CreateFrom1xBitmap(thumbnail);
   context.service->SetPageThumbnail(context, image);
   DVLOG(1) << "Thumbnail taken for " << context.url << ": "
       << context.score.ToString();
 
   CleanUpFromThumbnailGeneration();
 }
 
-void ThumbnailTabHelper::RenderViewHostCreated(
-    content::RenderViewHost* renderer) {
+void ThumbnailTabHelper::RenderViewHostCreated(RenderViewHost* renderer) {
   // NOTIFICATION_WEB_CONTENTS_RENDER_VIEW_HOST_CREATED is really a new
   // RenderView, not RenderViewHost, and there is no good way to get
   // notifications of RenderViewHosts. So just be tolerant of re-registrations.
   bool registered = registrar_.IsRegistered(
       this, content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
       content::Source<RenderWidgetHost>(renderer->GetWidget()));
   if (!registered) {
     registrar_.Add(this, content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
                    content::Source<RenderWidgetHost>(renderer->GetWidget()));
   }
 }
 
 void ThumbnailTabHelper::WidgetHidden(RenderWidgetHost* widget) {
   UpdateThumbnailIfNecessary();
 }