Throttle rendering pipeline for invisible frames

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

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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.
 
    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.
 */
 
 #ifndef FrameView_h
 #define FrameView_h
 
 #include "core/CoreExport.h"
+#include "core/dom/DocumentLifecycle.h"
 #include "core/frame/FrameViewAutoSizeInfo.h"
 #include "core/frame/LayoutSubtreeRootList.h"
 #include "core/frame/RootFrameViewport.h"
 #include "core/layout/LayoutAnalyzer.h"
 #include "core/paint/PaintPhase.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/Widget.h"
 #include "platform/geometry/IntRect.h"
 #include "platform/geometry/LayoutRect.h"
 #include "platform/graphics/Color.h"
 #include "platform/scroll/ScrollTypes.h"
 #include "platform/scroll/ScrollableArea.h"
 #include "platform/scroll/Scrollbar.h"
 #include "public/platform/WebDisplayMode.h"
 #include "public/platform/WebRect.h"
 #include "wtf/Allocator.h"
 #include "wtf/Forward.h"
 #include "wtf/HashSet.h"
 #include "wtf/ListHashSet.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/TemporaryChange.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class AXObjectCache;
+class CancellableTaskFactory;
 class ComputedStyle;
 class DocumentLifecycle;
 class Cursor;
 class Element;
 class FloatSize;
 class HTMLFrameOwnerElement;
 class LayoutPart;
 class LocalFrame;
 class KURL;
 class Node;
@@ skipping 153 matching lines @@
 
     void setIsPainting(bool val) const { m_isPainting = val; }
     bool isPainting() const;
 
     void setNodeToDraw(Node*);
     Node* nodeToDraw() const { return m_nodeToDraw.get(); }
 
     Color documentBackgroundColor() const;
 
     // Run all needed lifecycle stages. After calling this method, all frames will be in the lifecycle state PaintInvalidationClean.
+    // If lifecycle throttling is allowed (see DocumentLifecycle::PreventThrottlingScope), some frames may skip the lifecycle update
+    // (e.g., based on visibility) and will not end up being PaintInvalidationClean.
     // TODO(pdr): Update callers to pass in the interest rect.
     void updateAllLifecyclePhases(const LayoutRect* interestRect = nullptr);
 
     // Computes the style, layout and compositing lifecycle stages if needed. After calling this method, all frames wil lbe in a lifecycle
-    // state >= CompositingClean, and scrolling has been updated.
+    // state >= CompositingClean, and scrolling has been updated (unless throttling is allowed).
     void updateLifecycleToCompositingCleanPlusScrolling();
 
     // Computes only the style and layout lifecycle stages.
-    // After calling this method, all frames will be in a lifecycle state >= LayoutClean.
+    // After calling this method, all frames will be in a lifecycle state >= LayoutClean (unless throttling is allowed).
     void updateLifecycleToLayoutClean();
 
     bool invalidateViewportConstrainedObjects();
 
     void incrementVisuallyNonEmptyCharacterCount(unsigned);
     void incrementVisuallyNonEmptyPixelCount(const IntSize&);
     bool isVisuallyNonEmpty() const { return m_isVisuallyNonEmpty; }
     void setIsVisuallyNonEmpty() { m_isVisuallyNonEmpty = true; }
     void enableAutoSizeMode(const IntSize& minSize, const IntSize& maxSize);
     void disableAutoSizeMode();
@@ skipping 302 matching lines @@
     // Returns true if the default scrolling direction is vertical. i.e. writing mode
     // is horiziontal. In a vertical document, a spacebar scrolls down.
     bool isVerticalDocument() const;
 
     // Returns true if the document's writing mode is right-to-left or bottom-to-top.
     bool isFlippedDocument() const;
 
     void setFrameTimingRequestsDirty(bool isDirty) { m_frameTimingRequestsDirty = isDirty; }
     bool frameTimingRequestsDirty() { return m_frameTimingRequestsDirty; }
 
+    // Returns true if this frame should not render or schedule visual updates.
+    bool shouldThrottleRendering() const;
+
+    // Returns true if this frame could potentially skip rendering and avoid
+    // scheduling visual updates.
+    bool canThrottleRendering() const;
+    bool isHiddenForThrottling() const { return m_hiddenForThrottling; }
+
 protected:
     // Scroll the content via the compositor.
     bool scrollContentsFastPath(const IntSize& scrollDelta);
 
     // Scroll the content by invalidating everything.
     void scrollContentsSlowPath(const IntRect& updateRect);
 
     // These functions are used to create/destroy scrollbars.
     void setHasHorizontalScrollbar(bool);
     void setHasVerticalScrollbar(bool);
@@ skipping 142 matching lines @@
 
     void collectAnnotatedRegions(LayoutObject&, Vector<AnnotatedRegionValue>&) const;
 
     typedef WTF::HashMap <const GraphicsLayer*, Vector<std::pair<int64_t, WebRect>>> GraphicsLayerFrameTimingRequests;
     void updateFrameTimingRequestsIfNeeded();
     void collectFrameTimingRequests(GraphicsLayerFrameTimingRequests&);
     void collectFrameTimingRequestsRecursive(GraphicsLayerFrameTimingRequests&);
 
     template <typename Function> void forAllFrameViews(Function);
 
+    void setNeedsUpdateViewportIntersection();
+    void updateViewportIntersectionsForSubtree();
+    void updateViewportIntersectionIfNeeded();
+    void notifyIntersectionObservers();
+
     LayoutSize m_size;
 
     typedef HashSet<RefPtr<LayoutEmbeddedObject>> EmbeddedObjectSet;
     EmbeddedObjectSet m_partUpdateSet;
 
     // FIXME: These are just "children" of the FrameView and should be RefPtrWillBeMember<Widget> instead.
     HashSet<RefPtr<LayoutPart>> m_parts;
 
     // The RefPtr cycle between LocalFrame and FrameView is broken
     // when a LocalFrame is detached by LocalFrame::detach().
@@ skipping 14 matching lines @@
     bool m_hasPendingLayout;
     LayoutSubtreeRootList m_layoutSubtreeRootList;
 
     bool m_layoutSchedulingEnabled;
     bool m_inPerformLayout;
     bool m_inSynchronousPostLayout;
     int m_layoutCount;
     unsigned m_nestedLayoutCount;
     Timer<FrameView> m_postLayoutTasksTimer;
     Timer<FrameView> m_updateWidgetsTimer;
+    OwnPtr<CancellableTaskFactory> m_intersectionObserverNotificationFactory;
 
     bool m_firstLayout;
     bool m_isTransparent;
     Color m_baseBackgroundColor;
     IntSize m_lastViewportSize;
     float m_lastZoomFactor;
 
     AtomicString m_mediaType;
     AtomicString m_mediaTypeWhenNotPrinting;
 
@@ skipping 27 matching lines @@
     IntSize m_layoutSize;
     bool m_layoutSizeFixedToFrameSize;
 
     Timer<FrameView> m_didScrollTimer;
 
     Vector<IntRect> m_tickmarks;
 
     float m_topControlsViewportAdjustment;
 
     bool m_needsUpdateWidgetPositions;
+    bool m_needsUpdateViewportIntersection;
+    bool m_needsUpdateViewportIntersectionInSubtree;
 
 #if ENABLE(ASSERT)
     // Verified when finalizing.
     bool m_hasBeenDisposed;
 #endif
 
     RefPtrWillBeMember<Scrollbar> m_horizontalScrollbar;
     RefPtrWillBeMember<Scrollbar> m_verticalScrollbar;
     ScrollbarMode m_horizontalScrollbarMode;
     ScrollbarMode m_verticalScrollbarMode;
@@ skipping 15 matching lines @@
     OwnPtr<LayoutAnalyzer> m_analyzer;
 
     // Mark if something has changed in the mapping from Frame to GraphicsLayer
     // and the Frame Timing regions should be recalculated.
     bool m_frameTimingRequestsDirty;
 
     // Exists only on root frame.
     // TODO(bokan): crbug.com/484188. We should specialize FrameView for the
     // main frame.
     OwnPtrWillBeMember<ScrollableArea> m_viewportScrollableArea;
+
+    // This frame's bounds in the root frame's content coordinates, clipped
+    // recursively through every ancestor view.
+    IntRect m_viewportIntersection;
+    bool m_viewportIntersectionValid;
+
+    // The following members control rendering pipeline throttling for this
+    // frame. They are only updated in response to intersection observer
+    // notifications, i.e., not in the middle of the lifecycle.
+    bool m_hiddenForThrottling;
+    bool m_crossOriginForThrottling;
 };
 
 inline void FrameView::incrementVisuallyNonEmptyCharacterCount(unsigned count)
 {
     if (m_isVisuallyNonEmpty)
         return;
     m_visuallyNonEmptyCharacterCount += count;
     // Use a threshold value to prevent very small amounts of visible content from triggering didMeaningfulLayout.
     // The first few hundred characters rarely contain the interesting content of the page.
     static const unsigned visualCharacterThreshold = 200;
@@ skipping 10 matching lines @@
     static const unsigned visualPixelThreshold = 32 * 32;
     if (m_visuallyNonEmptyPixelCount > visualPixelThreshold)
         setIsVisuallyNonEmpty();
 }
 
 DEFINE_TYPE_CASTS(FrameView, Widget, widget, widget->isFrameView(), widget.isFrameView());
 
 } // namespace blink
 
 #endif // FrameView_h