Cross-origin iframes: collect data under hypothetical loading strategies

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "core/frame/FrameView.h"
 
+#include <algorithm>
 #include <memory>
 #include "core/HTMLNames.h"
 #include "core/MediaTypeNames.h"
 #include "core/animation/DocumentAnimations.h"
 #include "core/css/FontFaceSet.h"
 #include "core/dom/AXObjectCache.h"
 #include "core/dom/DOMNodeIds.h"
 #include "core/dom/ElementVisibilityObserver.h"
 #include "core/dom/Fullscreen.h"
 #include "core/dom/IntersectionObserverCallback.h"
@@ skipping 282 matching lines @@
   if (!targetElement)
     return;
 
   m_visibilityObserver = new ElementVisibilityObserver(
       targetElement, WTF::bind(
                          [](FrameView* frameView, bool isVisible) {
                            if (!frameView)
                              return;
                            frameView->updateRenderThrottlingStatus(
                                !isVisible, frameView->m_subtreeThrottled);
-                           frameView->maybeRecordLoadReason();
                          },
                          wrapWeakPersistent(this)));
   m_visibilityObserver->start();
 }
 
 void FrameView::dispose() {
   RELEASE_ASSERT(!isInPerformLayout());
 
   if (ScrollAnimatorBase* scrollAnimator = existingScrollAnimator())
     scrollAnimator->cancelAnimation();
@@ skipping 4404 matching lines @@
 void FrameView::updateViewportIntersectionsForSubtree(
     DocumentLifecycle::LifecycleState targetState) {
   // TODO(dcheng): Since widget tree updates are deferred, FrameViews might
   // still be in the widget hierarchy even though the associated Document is
   // already detached. Investigate if this check and a similar check in
   // lifecycle updates are still needed when there are no more deferred widget
   // updates: https://crbug.com/561683
   if (!frame().document()->isActive())
     return;
 
-  // Notify javascript IntersectionObservers
-  if (targetState == DocumentLifecycle::PaintClean &&
-      frame().document()->intersectionObserverController())
-    frame()
-        .document()
-        ->intersectionObserverController()
-        ->computeTrackedIntersectionObservations();
+  if (targetState == DocumentLifecycle::PaintClean) {
+    recordDeferredLoadingStats();
+    // Notify javascript IntersectionObservers
+    if (frame().document()->intersectionObserverController()) {
+      frame()
+          .document()
+          ->intersectionObserverController()
+          ->computeTrackedIntersectionObservations();
+    }
+  }
 
   // Don't throttle display:none frames (see updateRenderThrottlingStatus).
   HTMLFrameOwnerElement* ownerElement = m_frame->deprecatedLocalOwner();
   if (m_hiddenForThrottling && ownerElement && !ownerElement->layoutObject()) {
     // No need to notify children because descendants of display:none frames
     // should remain throttled.
     updateRenderThrottlingStatus(m_hiddenForThrottling, m_subtreeThrottled,
                                  DontForceThrottlingInvalidation,
                                  DontNotifyChildren);
     DCHECK(!canThrottleRendering());
@@ skipping 93 matching lines @@
 #if DCHECK_IS_ON()
   // Make sure we never have an unthrottled frame inside a throttled one.
   FrameView* parent = parentFrameView();
   while (parent) {
     DCHECK(canThrottleRendering() || !parent->canThrottleRendering());
     parent = parent->parentFrameView();
   }
 #endif
 }
 
-// TODO(esprehn): Rename this and the method on Document to
-// recordDeferredLoadReason().
-void FrameView::maybeRecordLoadReason() {
+void FrameView::recordDeferredLoadingStats() {
+  if (!frame().document()->frame() || !frame().isCrossOriginSubframe())
+    return;
+
   FrameView* parent = parentFrameView();
-  if (frame().document()->frame()) {
-    if (!parent) {
-      HTMLFrameOwnerElement* element = frame().deprecatedLocalOwner();
-      if (!element)
-        frame().document()->maybeRecordLoadReason(WouldLoadOutOfProcess);
-      // Having no layout object means the frame is not drawn.
-      else if (!element->layoutObject())
-        frame().document()->maybeRecordLoadReason(WouldLoadDisplayNone);
-    } else {
-      // Assume the main frame has always loaded since we don't track its
-      // visibility.
-      bool parentLoaded =
-          !parent->parentFrameView() ||
-          parent->frame().document()->wouldLoadReason() > Created;
-      // If the parent wasn't loaded, the children won't be either.
-      if (parentLoaded) {
-        if (frameRect().isEmpty())
-          frame().document()->maybeRecordLoadReason(WouldLoadZeroByZero);
-        else if (frameRect().maxY() < 0 && frameRect().maxX() < 0)
-          frame().document()->maybeRecordLoadReason(WouldLoadAboveAndLeft);
-        else if (frameRect().maxY() < 0)
-          frame().document()->maybeRecordLoadReason(WouldLoadAbove);
-        else if (frameRect().maxX() < 0)
-          frame().document()->maybeRecordLoadReason(WouldLoadLeft);
-        else if (!m_hiddenForThrottling)
-          frame().document()->maybeRecordLoadReason(WouldLoadVisible);
-      }
-    }
+  if (!parent) {
+    HTMLFrameOwnerElement* element = frame().deprecatedLocalOwner();
+    // We would fall into an else block on some teardowns and other weird cases.
+    if (!element || !element->layoutObject())
+      frame().document()->recordDeferredLoadReason(WouldLoadNoParent);
+    return;
   }
+  // Small inaccuracy: frames with origins that match the top level might be
+  // nested in a cross-origin frame. To keep code simpler, count such frames as
+  // WouldLoadVisible, even when their parent is offscreen.
+  WouldLoadReason whyParentLoaded = WouldLoadVisible;
+  if (parent->parentFrameView() && parent->frame().isCrossOriginSubframe())
+    whyParentLoaded = parent->frame().document()->deferredLoadReason();
+
+  // If the parent wasn't loaded, the children won't be either.
+  if (whyParentLoaded == Created)
+    return;
+  // These frames are never meant to be seen so we will need to load them.
+  if (frameRect().isEmpty() || frameRect().maxY() < 0 ||
+      frameRect().maxX() < 0) {
+    frame().document()->recordDeferredLoadReason(whyParentLoaded);
+    return;
+  }
+
+  IntRect parentRect = parent->frameRect();
+  // First clause: for this rough data collection we assume the user never
+  // scrolls right.
+  if (frameRect().x() >= parentRect.width() || parentRect.height() <= 0)
+    return;
+
+  int thisFrameScreensAway = 0;
+  // If an frame is created above the current scoll position, this logic counts
+  // it as visible.
+  if (frameRect().y() > parent->getScrollOffset().height()) {
+    thisFrameScreensAway =
+        (frameRect().y() - parent->getScrollOffset().height()) /
+        parentRect.height();
+  }
+  DCHECK_GE(thisFrameScreensAway, 0);
+
+  int parentScreensAway = 0;
+  if (whyParentLoaded <= WouldLoadVisible)
+    parentScreensAway = WouldLoadVisible - whyParentLoaded;
+
+  int totalScreensAway = thisFrameScreensAway + parentScreensAway;
+
+  // We're collecting data for frames that are at most 3 screens away.
+  if (totalScreensAway > 3)
+    return;
+
+  frame().document()->recordDeferredLoadReason(
+      static_cast<WouldLoadReason>(WouldLoadVisible - totalScreensAway));
 }
 
 bool FrameView::shouldThrottleRendering() const {
   return canThrottleRendering() && m_frame->document() &&
          lifecycle().throttlingAllowed();
 }
 
 bool FrameView::canThrottleRendering() const {
   if (m_lifecycleUpdatesThrottled)
     return true;
@@ skipping 300 matching lines @@
 void FrameView::setAnimationHost(
     std::unique_ptr<CompositorAnimationHost> host) {
   m_animationHost = std::move(host);
 }
 
 LayoutUnit FrameView::caretWidth() const {
   return LayoutUnit(getHostWindow()->windowToViewportScalar(1));
 }
 
 }  // namespace blink