Throttle rendering pipeline for invisible iframes

Source/core/paint/DeprecatedPaintLayerPainter.cpp

 // Copyright 2014 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 "config.h"
 #include "core/paint/DeprecatedPaintLayerPainter.h"
 
 #include "core/frame/Settings.h"
 #include "core/layout/ClipPathOperation.h"
 #include "core/layout/LayoutBlock.h"
+#include "core/layout/LayoutFrame.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/svg/LayoutSVGResourceClipper.h"
 #include "core/page/Page.h"
 #include "core/paint/CompositingRecorder.h"
 #include "core/paint/DeprecatedPaintLayer.h"
 #include "core/paint/FilterPainter.h"
 #include "core/paint/LayerClipRecorder.h"
 #include "core/paint/LayerFixedPositionRecorder.h"
 #include "core/paint/PaintInfo.h"
 #include "core/paint/SVGClipPainter.h"
@@ skipping 16 matching lines @@
 {
     // Avoid painting descendants of the root layer when stylesheets haven't loaded. This eliminates FOUC.
     // It's ok not to draw, because later on, when all the stylesheets do load, updateStyleSelector on the Document
     // will do a full paintInvalidationForWholeLayoutObject().
     if (layer->layoutObject()->document().didLayoutWithPendingStylesheets() && !layer->isRootLayer() && !layer->layoutObject()->isDocumentElement())
         return true;
 
     return false;
 }
 
+static bool isThrottledFrameView(const LayoutObject* layoutObject)
+{
+    if (!layoutObject->isLayoutPart())
+        return false;
+    const LayoutPart* part = toLayoutPart(layoutObject);
+    if (!part->widget() || !part->widget()->isFrameView())
+        return false;
+    const FrameView* frameView = toFrameView(part->widget());
+    return frameView->shouldThrottleRenderingPipeline();
+}
+
 void DeprecatedPaintLayerPainter::paint(GraphicsContext* context, const LayoutRect& damageRect, const GlobalPaintFlags globalPaintFlags, LayoutObject* paintingRoot, PaintLayerFlags paintFlags)
 {
     DeprecatedPaintLayerPaintingInfo paintingInfo(&m_paintLayer, LayoutRect(enclosingIntRect(damageRect)), globalPaintFlags, LayoutSize(), paintingRoot);
     if (shouldPaintLayerInSoftwareMode(globalPaintFlags, paintFlags))
         paintLayer(context, paintingInfo, paintFlags);
 }
 
 static ShouldRespectOverflowClip shouldRespectOverflowClip(PaintLayerFlags paintFlags, const LayoutObject* layoutObject)
 {
     return (paintFlags & PaintLayerPaintingOverflowContents || (paintFlags & PaintLayerPaintingChildClippingMaskPhase && layoutObject->hasClipPath())) ? IgnoreOverflowClip : RespectOverflowClip;
@@ skipping 21 matching lines @@
 
     // Non self-painting leaf layers don't need to be painted as their layoutObject() should properly paint itself.
     if (!m_paintLayer.isSelfPaintingLayer() && !m_paintLayer.hasSelfPaintingLayerDescendant()) {
         ASSERT(!m_paintLayer.needsRepaint());
         return FullyPainted;
     }
 
     if (shouldSuppressPaintingLayer(&m_paintLayer))
         return FullyPainted;
 
+    // TODO(skyostil): Unify this early-out logic with subsequence caching.
+    if (isThrottledFrameView(m_paintLayer.layoutObject()))
+        return FullyPainted;
+
     // If this layer is totally invisible then there is nothing to paint.
     if (!m_paintLayer.layoutObject()->opacity() && !m_paintLayer.layoutObject()->hasBackdropFilter())
         return FullyPainted;
 
     if (m_paintLayer.paintsWithTransparency(paintingInfo.globalPaintFlags()))
         paintFlags |= PaintLayerHaveTransparency;
 
     LayerFixedPositionRecorder fixedPositionRecorder(*context, *m_paintLayer.layoutObject());
 
     // PaintLayerAppliedTransform is used in LayoutReplica, to avoid applying the transform twice.
@@ skipping 120 matching lines @@
     Optional<SubsequenceRecorder> subsequenceRecorder;
     if (isPaintingOverlayScrollbars) {
         // We should have cleared the repaint flag in the first pass.
         ASSERT(!needsRepaint);
     } else {
         if (!needsRepaint && SubsequenceRecorder::useCachedSubsequenceIfPossible(*context, m_paintLayer))
             return result;
         subsequenceRecorder.emplace(*context, m_paintLayer);
     }
 
+    // TODO(skyostil): Unify this early-out logic with subsequence caching.
+    if (isThrottledFrameView(m_paintLayer.layoutObject()))
+        return FullyPainted;
+
     DeprecatedPaintLayerPaintingInfo paintingInfo = paintingInfoArg;
 
     // Ensure our lists are up-to-date.
     m_paintLayer.stackingNode()->updateLayerListsIfNeeded();
 
     LayoutPoint offsetFromRoot;
     m_paintLayer.convertToLayerCoords(paintingInfo.rootLayer, offsetFromRoot);
 
     if (m_paintLayer.compositingState() == PaintsIntoOwnBacking)
         offsetFromRoot.move(m_paintLayer.subpixelAccumulation());
@@ skipping 430 matching lines @@
     if (!m_paintLayer.containsDirtyOverlayScrollbars())
         return;
 
     DeprecatedPaintLayerPaintingInfo paintingInfo(&m_paintLayer, LayoutRect(enclosingIntRect(damageRect)), paintFlags, LayoutSize(), paintingRoot);
     paintLayer(context, paintingInfo, PaintLayerPaintingOverlayScrollbars);
 
     m_paintLayer.setContainsDirtyOverlayScrollbars(false);
 }
 
 } // namespace blink