Throttle rendering pipeline for invisible iframes

Source/core/paint/DeprecatedPaintLayerPainter.cpp

Index: Source/core/paint/DeprecatedPaintLayerPainter.cpp
diff --git a/Source/core/paint/DeprecatedPaintLayerPainter.cpp b/Source/core/paint/DeprecatedPaintLayerPainter.cpp
index b377cdfe02ee91c70e0e96d8affed000d1cd5b5d..79cbbf85516fa2c6e9bec8d1536b4fa7295e7dff 100644
--- a/Source/core/paint/DeprecatedPaintLayerPainter.cpp
+++ b/Source/core/paint/DeprecatedPaintLayerPainter.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"
@@ -43,6 +44,17 @@ static inline bool shouldSuppressPaintingLayer(DeprecatedPaintLayer* layer)
     return false;
 }
 
+static bool isThrottledFrameView(const LayoutObject* layoutObject)
+{
+    if (!layoutObject->isFrame())
+        return false;
+    const LayoutFrame* frame = toLayoutFrame(layoutObject);
+    if (!frame->widget()->isFrameView())
+        return false;
+    const FrameView* frameView = toFrameView(frame->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);
@@ -80,6 +92,9 @@ void DeprecatedPaintLayerPainter::paintLayer(GraphicsContext* context, const Dep
     if (shouldSuppressPaintingLayer(&m_paintLayer))
         return;
 
+    if (isThrottledFrameView(m_paintLayer.layoutObject()))

[chrishtr, 2015/09/04 17:32:04]

Add TODO here and below about subsequence caching.

[Sami, 2015/09/07 17:27:17]

Done.

+        return;
+
     // If this layer is totally invisible then there is nothing to paint.
     if (!m_paintLayer.layoutObject()->opacity() && !m_paintLayer.layoutObject()->hasBackdropFilter())
         return;
@@ -203,6 +218,9 @@ void DeprecatedPaintLayerPainter::paintLayerContents(GraphicsContext* context, c
     if (paintFlags & PaintLayerPaintingRootBackgroundOnly && !m_paintLayer.layoutObject()->isLayoutView() && !m_paintLayer.layoutObject()->isDocumentElement())
         return;
 
+    if (isThrottledFrameView(m_paintLayer.layoutObject()))
+        return;
+
     // Ensure our lists are up-to-date.
     m_paintLayer.stackingNode()->updateLayerListsIfNeeded();