Refactor ResourceLoadPriorityOptimizer to avoid walking render tree

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.
  *
@@ skipping 94 matching lines @@
 // The balance between CPU use and repaint frequency will need some tuning for desktop.
 // More hooks may be needed to reset the delay on things like GIF and CSS animations.
 double FrameView::s_normalDeferredRepaintDelay = 0;
 double FrameView::s_initialDeferredRepaintDelayDuringLoading = 0;
 double FrameView::s_maxDeferredRepaintDelayDuringLoading = 0;
 double FrameView::s_deferredRepaintDelayIncrementDuringLoading = 0;
 #endif
 
 // The maximum number of updateWidgets iterations that should be done before returning.
 static const unsigned maxUpdateWidgetsIterations = 2;
+static const double resourcePriorityUpdateDelayAfterScroll = 0.250;
 
 static RenderLayer::UpdateLayerPositionsFlags updateLayerPositionFlags(RenderLayer* layer, bool isRelayoutingSubtree, bool didFullRepaint)
 {
     RenderLayer::UpdateLayerPositionsFlags flags = RenderLayer::defaultFlags;
 
     if (didFullRepaint) {
         flags &= ~RenderLayer::CheckForRepaint;
         flags |= RenderLayer::NeedsFullRepaintInBacking;
     }
     if (isRelayoutingSubtree && layer->isPaginated())
@@ skipping 61 matching lines @@
     , m_shouldUpdateWhileOffscreen(true)
     , m_scrollCorner(0)
     , m_shouldAutoSize(false)
     , m_inAutoSize(false)
     , m_didRunAutosize(false)
     , m_hasSoftwareFilters(false)
     , m_visibleContentScaleFactor(1)
     , m_inputEventsScaleFactorForEmulation(1)
     , m_partialLayout()
     , m_layoutSizeFixedToFrameSize(true)
+    , m_didScrollTimer(this, &FrameView::didScrollTimerFired)
 {
     ASSERT(m_frame);
     init();
 
     if (!isMainFrame())
         return;
 
     ScrollableArea::setVerticalScrollElasticity(ScrollElasticityAllowed);
     ScrollableArea::setHorizontalScrollElasticity(ScrollElasticityAllowed);
 }
@@ skipping 13 matching lines @@
 
     view->show();
     return view.release();
 }
 
 FrameView::~FrameView()
 {
     if (m_postLayoutTasksTimer.isActive())
         m_postLayoutTasksTimer.stop();
 
+    if (m_didScrollTimer.isActive())
+        m_didScrollTimer.stop();
+
     removeFromAXObjectCache();
     resetScrollbars();
 
     // Custom scrollbars should already be destroyed at this point
     ASSERT(!horizontalScrollbar() || !horizontalScrollbar()->isCustomScrollbar());
     ASSERT(!verticalScrollbar() || !verticalScrollbar()->isCustomScrollbar());
 
     setHasHorizontalScrollbar(false); // Remove native scrollbars now before we lose the connection to the HostWindow.
     setHasVerticalScrollbar(false);
 
@@ skipping 674 matching lines @@
 
         // Text Autosizing requires two-pass layout which is incompatible with partial layout.
         // If enabled, only do partial layout for the second layout.
         // FIXME (crbug.com/256657): Do not do two layouts for text autosizing.
         PartialLayoutDisabler partialLayoutDisabler(partialLayout(), m_frame->settings() && m_frame->settings()->textAutosizingEnabled());
 
         LayoutIndicator layoutIndicator;
         rootForThisLayout->layout();
         gatherDebugLayoutRects(rootForThisLayout);
 
-        ResourceLoadPriorityOptimizer modifier;
-        rootForThisLayout->didLayout(modifier);
+        ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->updateAllImageResourcePriorities();
     }
 
     TextAutosizer* textAutosizer = frame().document()->textAutosizer();
     bool autosized = textAutosizer && textAutosizer->processSubtree(rootForThisLayout);
     if (autosized && rootForThisLayout->needsLayout()) {
         TRACE_EVENT0("webkit", "2nd layout due to Text Autosizing");
         LayoutIndicator layoutIndicator;
         rootForThisLayout->layout();
         gatherDebugLayoutRects(rootForThisLayout);
-
-        ResourceLoadPriorityOptimizer modifier;
-        rootForThisLayout->didLayout(modifier);
     }
 
     m_inLayout = false;
 
     if (inSubtreeLayout)
         rootForThisLayout->view()->popLayoutState(rootForThisLayout);
 }
 
 void FrameView::scheduleOrPerformPostLayoutTasks()
 {
@@ skipping 772 matching lines @@
     Document* document = m_frame->document();
     document->enqueueScrollEventForNode(document);
 
     m_frame->eventHandler().dispatchFakeMouseMoveEventSoon();
 
     if (RenderView* renderView = document->renderView()) {
         if (renderView->usesCompositing())
             renderView->compositor()->frameViewDidScroll();
     }
 
+    if (m_didScrollTimer.isActive())
+        m_didScrollTimer.stop();
+    m_didScrollTimer.startOneShot(resourcePriorityUpdateDelayAfterScroll);
+}
+
+void FrameView::didScrollTimerFired(Timer<FrameView>*)
+{
     if (m_frame->document() && m_frame->document()->renderer()) {
-        ResourceLoadPriorityOptimizer modifier;
-        m_frame->document()->renderer()->didScroll(modifier);
+        ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->updateAllImageResourcePriorities();
     }
 }
 
 void FrameView::repaintFixedElementsAfterScrolling()
 {
     // For fixed position elements, update widget positions and compositing layers after scrolling,
     // but only if we're not inside of layout.
     if (!m_nestedLayoutCount && hasViewportConstrainedObjects()) {
         if (RenderView* renderView = this->renderView()) {
             renderView->updateWidgetPositions();
@@ skipping 1768 matching lines @@
 void FrameView::willRemoveScrollbar(Scrollbar* scrollbar, ScrollbarOrientation orientation)
 {
     ScrollableArea::willRemoveScrollbar(scrollbar, orientation);
     if (AXObjectCache* cache = axObjectCache()) {
         cache->remove(scrollbar);
         cache->handleScrollbarUpdate(this);
     }
 }
 
 } // namespace WebCore