Throttle rendering pipeline for invisible frames

third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp b/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
index 6aa124823e87b7dca13e33f0cf0d8f9728cae97a..c3bc70a2a1e08ecc9423289bb9d046e784cc6b8f 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
@@ -8,6 +8,7 @@
 #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"
@@ -44,6 +45,17 @@ static inline bool shouldSuppressPaintingLayer(PaintLayer* layer)
     return false;
 }
 
+static bool isThrottledFrameView(const LayoutObject* layoutObject)

[esprehn, 2015/10/14 22:09:46]

I'd put this on LayoutPart, and do 

->isLayoutPart() && toLayoutPart(thing)->isThrottledFrameView()

at the two callers

[Sami, 2015/10/16 16:48:09]

Thanks, much better.

+{
+    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->shouldThrottleRendering();
+}
+
 void PaintLayerPainter::paint(GraphicsContext* context, const LayoutRect& damageRect, const GlobalPaintFlags globalPaintFlags, LayoutObject* paintingRoot, PaintLayerFlags paintFlags)
 {
     PaintLayerPaintingInfo paintingInfo(&m_paintLayer, LayoutRect(enclosingIntRect(damageRect)), globalPaintFlags, LayoutSize(), paintingRoot);
@@ -86,6 +98,10 @@ PaintLayerPainter::PaintResult PaintLayerPainter::paintLayerInternal(GraphicsCon
     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;
@@ -220,6 +236,10 @@ PaintLayerPainter::PaintResult PaintLayerPainter::paintLayerContentsInternal(Gra
     if (paintFlags & PaintLayerPaintingRootBackgroundOnly && !m_paintLayer.layoutObject()->isLayoutView() && !m_paintLayer.layoutObject()->isDocumentElement())
         return result;
 
+    // TODO(skyostil): Unify this early-out logic with subsequence caching.
+    if (isThrottledFrameView(m_paintLayer.layoutObject()))
+        return FullyPainted;
+
     PaintLayerPaintingInfo paintingInfo = paintingInfoArg;
 
     // Ensure our lists are up-to-date.