Reland of remove EventSender from ImageLoader

third_party/WebKit/Source/core/loader/ImageLoader.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010 Apple Inc. All rights
  * reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 11 matching lines @@
 
 #include "core/loader/ImageLoader.h"
 
 #include <memory>
 #include "bindings/core/v8/ScriptController.h"
 #include "bindings/core/v8/V8BindingForCore.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/IncrementLoadEventDelayCount.h"
 #include "core/events/Event.h"
-#include "core/events/EventSender.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/frame/UseCounter.h"
 #include "core/html/CrossOriginAttribute.h"
 #include "core/html/HTMLImageElement.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "core/layout/LayoutImage.h"
 #include "core/layout/LayoutVideo.h"
 #include "core/layout/svg/LayoutSVGImage.h"
 #include "core/probe/CoreProbes.h"
 #include "core/svg/graphics/SVGImage.h"
 #include "platform/bindings/Microtask.h"
 #include "platform/bindings/ScriptState.h"
 #include "platform/bindings/V8PerIsolateData.h"
 #include "platform/loader/fetch/FetchParameters.h"
 #include "platform/loader/fetch/MemoryCache.h"
 #include "platform/loader/fetch/ResourceFetcher.h"
 #include "platform/loader/fetch/ResourceLoadingLog.h"
 #include "platform/weborigin/SecurityOrigin.h"
 #include "platform/weborigin/SecurityPolicy.h"
 #include "platform/wtf/PtrUtil.h"
 #include "public/platform/WebCachePolicy.h"
 #include "public/platform/WebURLRequest.h"
 
 namespace blink {
 
-static ImageEventSender& LoadEventSender() {
-  DEFINE_STATIC_LOCAL(ImageEventSender, sender,
-                      (ImageEventSender::Create(EventTypeNames::load)));
-  return sender;
-}
-
-static ImageEventSender& ErrorEventSender() {
-  DEFINE_STATIC_LOCAL(ImageEventSender, sender,
-                      (ImageEventSender::Create(EventTypeNames::error)));
-  return sender;
-}
-
 static inline bool PageIsBeingDismissed(Document* document) {
   return document->PageDismissalEventBeingDispatched() !=
          Document::kNoDismissal;
 }
 
 static ImageLoader::BypassMainWorldBehavior ShouldBypassMainWorldCSP(
     ImageLoader* loader) {
   DCHECK(loader);
   DCHECK(loader->GetElement());
   if (loader->GetElement()->GetDocument().GetFrame() &&
@@ skipping 68 matching lines @@
   BypassMainWorldBehavior should_bypass_main_world_csp_;
   UpdateFromElementBehavior update_behavior_;
   RefPtr<ScriptState> script_state_;
   WeakPtrFactory<Task> weak_factory_;
   ReferrerPolicy referrer_policy_;
   KURL request_url_;
 };
 
 ImageLoader::ImageLoader(Element* element)
     : element_(element),
-      has_pending_load_event_(false),
-      has_pending_error_event_(false),
       image_complete_(true),
       loading_image_document_(false),
       suppress_error_events_(false) {
   RESOURCE_LOADING_DVLOG(1) << "new ImageLoader " << this;
 }
 
 ImageLoader::~ImageLoader() {}
 
 void ImageLoader::Dispose() {
   RESOURCE_LOADING_DVLOG(1)
       << "~ImageLoader " << this
-      << "; has_pending_load_event_=" << has_pending_load_event_
-      << ", has_pending_error_event_=" << has_pending_error_event_;
+      << "; has pending load event=" << pending_load_event_.IsActive()
+      << ", has pending error event=" << pending_error_event_.IsActive();
 
   if (image_) {
     image_->RemoveObserver(this);
     image_ = nullptr;
     delay_until_image_notify_finished_ = nullptr;
   }
 }
 
 DEFINE_TRACE(ImageLoader) {
   visitor->Trace(image_);
@@ skipping 22 matching lines @@
   // loading is just started.
   // TODO(hiroshige): clean up the behavior of flags. https://crbug.com/719759
   image_complete_ = true;
 }
 
 void ImageLoader::SetImageWithoutConsideringPendingLoadEvent(
     ImageResourceContent* new_image) {
   DCHECK(failed_load_url_.IsEmpty());
   ImageResourceContent* old_image = image_.Get();
   if (new_image != old_image) {
-    if (has_pending_load_event_) {
-      LoadEventSender().CancelEvent(this);
-      has_pending_load_event_ = false;
-    }
-    if (has_pending_error_event_) {
-      ErrorEventSender().CancelEvent(this);
-      has_pending_error_event_ = false;
-    }
+    if (pending_load_event_.IsActive())
+      pending_load_event_.Cancel();
+    if (pending_error_event_.IsActive())
+      pending_error_event_.Cancel();
     UpdateImageState(new_image);
     if (new_image) {
       new_image->AddObserver(this);
     }
     if (old_image) {
       old_image->RemoveObserver(this);
     }
   }
 
   if (LayoutImageResource* image_resource = GetLayoutImageResource())
@@ skipping 16 matching lines @@
   }
 
   if (client_hints_preferences.ShouldSendResourceWidth() &&
       isHTMLImageElement(element))
     params.SetResourceWidth(toHTMLImageElement(element).GetResourceWidth());
 }
 
 inline void ImageLoader::DispatchErrorEvent() {
   // There can be cases where DispatchErrorEvent() is called when there is
   // already a scheduled error event for the previous load attempt.
-  // In such cases we cancel the previous event and then re-schedule a new
-  // error event here. crbug.com/722500
-  if (has_pending_error_event_)
-    ErrorEventSender().CancelEvent(this);
-
-  has_pending_error_event_ = true;
-  ErrorEventSender().DispatchEventSoon(this);
+  // In such cases we cancel the previous event (by overwriting
+  // |pending_error_event_|) and then re-schedule a new error event here.
+  // crbug.com/722500
+  pending_error_event_ =
+      TaskRunnerHelper::Get(TaskType::kDOMManipulation,
+                            &GetElement()->GetDocument())
+          ->PostCancellableTask(
+              BLINK_FROM_HERE,
+              WTF::Bind(&ImageLoader::DispatchPendingErrorEvent,
+                        WrapPersistent(this),
+                        WTF::Passed(IncrementLoadEventDelayCount::Create(
+                            GetElement()->GetDocument()))));
 }
 
 inline void ImageLoader::CrossSiteOrCSPViolationOccurred(
     AtomicString image_source_url) {
   failed_load_url_ = image_source_url;
 }
 
 inline void ImageLoader::ClearFailedLoadURL() {
   failed_load_url_ = AtomicString();
 }
@@ skipping 81 matching lines @@
       DispatchErrorEvent();
     }
     NoImageResourceToLoad();
   }
 
   ImageResourceContent* old_image = image_.Get();
   if (update_behavior == kUpdateSizeChanged && element_->GetLayoutObject() &&
       element_->GetLayoutObject()->IsImage() && new_image == old_image) {
     ToLayoutImage(element_->GetLayoutObject())->IntrinsicSizeChanged();
   } else {
-    if (has_pending_load_event_) {
-      LoadEventSender().CancelEvent(this);
-      has_pending_load_event_ = false;
-    }
+    if (pending_load_event_.IsActive())
+      pending_load_event_.Cancel();
 
     // Cancel error events that belong to the previous load, which is now
     // cancelled by changing the src attribute. If newImage is null and
     // has_pending_error_event_ is true, we know the error event has been just
     // posted by this load and we should not cancel the event.
     // FIXME: If both previous load and this one got blocked with an error, we
     // can receive one error event instead of two.
-    if (has_pending_error_event_ && new_image) {
-      ErrorEventSender().CancelEvent(this);
-      has_pending_error_event_ = false;
-    }
+    if (pending_error_event_.IsActive() && new_image)
+      pending_error_event_.Cancel();
 
     UpdateImageState(new_image);
 
     UpdateLayoutObject();
     // If newImage exists and is cached, addObserver() will result in the load
     // event being queued to fire. Ensure this happens after beforeload is
     // dispatched.
     if (new_image) {
       new_image->AddObserver(this);
     }
@@ skipping 114 matching lines @@
   if (!document.IsActive())
     return;
 
   delay_until_image_notify_finished_ =
       IncrementLoadEventDelayCount::Create(document);
 }
 
 void ImageLoader::ImageNotifyFinished(ImageResourceContent* resource) {
   RESOURCE_LOADING_DVLOG(1)
       << "ImageLoader::imageNotifyFinished " << this
-      << "; has_pending_load_event_=" << has_pending_load_event_;
+      << "; has pending load event=" << pending_load_event_.IsActive();
 
   DCHECK(failed_load_url_.IsEmpty());
   DCHECK_EQ(resource, image_.Get());
 
   // |image_complete_| is always true for entire ImageDocument loading for
   // historical reason.
   // DoUpdateFromElement() is not called and SetImageForImageDocument()
   // is called instead for ImageDocument loading.
   // TODO(hiroshige): Turn the CHECK()s to DCHECK()s before going to beta.
   if (loading_image_document_)
@@ skipping 15 matching lines @@
     // checks, which can occur anytime after ImageNotifyFinished()
     // (See SVGImage::CurrentFrameHasSingleSecurityOrigin()).
     // We check the document is loaded here to catch violation of the
     // assumption reliably.
     ToSVGImage(image_->GetImage())->CheckLoaded();
 
     ToSVGImage(image_->GetImage())
         ->UpdateUseCounters(GetElement()->GetDocument());
   }
 
-  if (loading_image_document_)
+  if (loading_image_document_) {
+    CHECK(!pending_load_event_.IsActive());
     return;
+  }
 
   if (resource->ErrorOccurred()) {
-    LoadEventSender().CancelEvent(this);
-    has_pending_load_event_ = false;
+    pending_load_event_.Cancel();
 
     if (resource->GetResourceError().IsAccessCheck()) {
       CrossSiteOrCSPViolationOccurred(
           AtomicString(resource->GetResourceError().FailingURL()));
     }
 
     // The error event should not fire if the image data update is a result of
     // environment change.
     // https://html.spec.whatwg.org/multipage/embedded-content.html#the-img-element:the-img-element-55
     if (!suppress_error_events_)
       DispatchErrorEvent();
     return;
   }
-  has_pending_load_event_ = true;
-  LoadEventSender().DispatchEventSoon(this);
+
+  CHECK(!pending_load_event_.IsActive());
+  pending_load_event_ =
+      TaskRunnerHelper::Get(TaskType::kDOMManipulation,
+                            &GetElement()->GetDocument())
+          ->PostCancellableTask(
+              BLINK_FROM_HERE,
+              WTF::Bind(&ImageLoader::DispatchPendingLoadEvent,
+                        WrapPersistent(this),
+                        WTF::Passed(IncrementLoadEventDelayCount::Create(
+                            GetElement()->GetDocument()))));
 }
 
 LayoutImageResource* ImageLoader::GetLayoutImageResource() {
   LayoutObject* layout_object = element_->GetLayoutObject();
 
   if (!layout_object)
     return 0;
 
   // We don't return style generated image because it doesn't belong to the
   // ImageLoader. See <https://bugs.webkit.org/show_bug.cgi?id=42840>
@@ skipping 22 matching lines @@
   ImageResourceContent* cached_image = image_resource->CachedImage();
   if (image_ != cached_image && (image_complete_ || !cached_image))
     image_resource->SetImageResource(image_.Get());
 }
 
 bool ImageLoader::HasPendingEvent() const {
   // Regular image loading is in progress.
   if (image_ && !image_complete_ && !loading_image_document_)
     return true;
 
-  if (has_pending_load_event_ || has_pending_error_event_)
+  if (pending_load_event_.IsActive() || pending_error_event_.IsActive())
     return true;
 
   return false;
 }
 
-void ImageLoader::DispatchPendingEvent(ImageEventSender* event_sender) {
-  RESOURCE_LOADING_DVLOG(1) << "ImageLoader::dispatchPendingEvent " << this;
-  DCHECK(event_sender == &LoadEventSender() ||
-         event_sender == &ErrorEventSender());
-  const AtomicString& event_type = event_sender->EventType();
-  if (event_type == EventTypeNames::load)
-    DispatchPendingLoadEvent();
-  if (event_type == EventTypeNames::error)
-    DispatchPendingErrorEvent();
-}
-
-void ImageLoader::DispatchPendingLoadEvent() {
-  CHECK(has_pending_load_event_);
+void ImageLoader::DispatchPendingLoadEvent(
+    std::unique_ptr<IncrementLoadEventDelayCount> count) {
   if (!image_)
     return;
   CHECK(image_complete_);
-  has_pending_load_event_ = false;
   if (GetElement()->GetDocument().GetFrame())
     DispatchLoadEvent();
+
+  // Checks Document's load event synchronously here for performance.
+  // This is safe because DispatchPendingLoadEvent() is called asynchronously.
+  count->ClearAndCheckLoadEvent();
 }
 
-void ImageLoader::DispatchPendingErrorEvent() {
-  CHECK(has_pending_error_event_);
-  has_pending_error_event_ = false;
-
+void ImageLoader::DispatchPendingErrorEvent(
+    std::unique_ptr<IncrementLoadEventDelayCount> count) {
   if (GetElement()->GetDocument().GetFrame())
     GetElement()->DispatchEvent(Event::Create(EventTypeNames::error));
+
+  // Checks Document's load event synchronously here for performance.
+  // This is safe because DispatchPendingErrorEvent() is called asynchronously.
+  count->ClearAndCheckLoadEvent();
 }
 
 bool ImageLoader::GetImageAnimationPolicy(ImageAnimationPolicy& policy) {
   if (!GetElement()->GetDocument().GetSettings())
     return false;
 
   policy = GetElement()->GetDocument().GetSettings()->GetImageAnimationPolicy();
   return true;
 }
 
-void ImageLoader::DispatchPendingLoadEvents() {
-  LoadEventSender().DispatchPendingEvents();
-}
-
-void ImageLoader::DispatchPendingErrorEvents() {
-  ErrorEventSender().DispatchPendingEvents();
-}
-
 void ImageLoader::ElementDidMoveToNewDocument() {
   if (delay_until_do_update_from_element_) {
     delay_until_do_update_from_element_->DocumentChanged(
         element_->GetDocument());
   }
   if (delay_until_image_notify_finished_) {
     delay_until_image_notify_finished_->DocumentChanged(
         element_->GetDocument());
   }
   ClearFailedLoadURL();
   ClearImage();
 }
 
 }  // namespace blink