Disentangle repaint-after-compositing from updateLayerPositionsAfterLayout

Source/core/rendering/PaintInvalidationState.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/rendering/PaintInvalidationState.h"
 
 #include "core/rendering/RenderInline.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/svg/RenderSVGModelObject.h"
 #include "platform/Partitions.h"
 
 namespace blink {
 
 PaintInvalidationState::PaintInvalidationState(RenderObject& renderer)
     : m_clipped(false)
     , m_cachedOffsetsEnabled(true)
+    , m_forceCheckForPaintInvalidation(false)
     , m_paintInvalidationContainer(*renderer.containerForPaintInvalidation())
     , m_renderer(renderer)
 {
     bool establishesPaintInvalidationContainer = &m_renderer == &m_paintInvalidationContainer;
     if (!establishesPaintInvalidationContainer) {
         if (!renderer.supportsLayoutStateCachedOffsets()) {
             m_cachedOffsetsEnabled = false;
             return;
         }
         bool invalidationContainerSkipped;
         RenderObject* container = renderer.container(&m_paintInvalidationContainer, &invalidationContainerSkipped);
         if (container && !invalidationContainerSkipped) {
             FloatPoint point = container->localToContainerPoint(FloatPoint(), &m_paintInvalidationContainer);
             if (container->isTableRow())
                 point = FloatPoint(point.x() - toRenderBox(container)->x().toFloat(), point.y() - toRenderBox(container)->y().toFloat());
             m_paintOffset = LayoutSize(point.x(), point.y());
 
             applyClipIfNeeded(*container);
         }
     } else {
         applyClipIfNeeded(m_renderer);
     }
 }
 
 PaintInvalidationState::PaintInvalidationState(const PaintInvalidationState& next, RenderSVGModelObject& renderer, const RenderLayerModelObject& paintInvalidationContainer)
     : m_clipped(next.m_clipped)
     , m_cachedOffsetsEnabled(next.m_cachedOffsetsEnabled)
+    , m_forceCheckForPaintInvalidation(next.m_forceCheckForPaintInvalidation)
     , m_paintInvalidationContainer(paintInvalidationContainer)
     , m_renderer(renderer)
 {
     // FIXME: SVG could probably benefit from a stack-based optimization like html does. crbug.com/391054
     ASSERT(!m_cachedOffsetsEnabled);
 }
 
 PaintInvalidationState::PaintInvalidationState(const PaintInvalidationState& next, RenderInline& renderer, const RenderLayerModelObject& paintInvalidationContainer)
     : m_clipped(false)
     , m_cachedOffsetsEnabled(true)
+    , m_forceCheckForPaintInvalidation(next.m_forceCheckForPaintInvalidation)
     , m_paintInvalidationContainer(paintInvalidationContainer)
     , m_renderer(renderer)
 {
     bool establishesPaintInvalidationContainer = &m_renderer == &m_paintInvalidationContainer;
-    if (!establishesPaintInvalidationContainer) {
+    if (establishesPaintInvalidationContainer) {
+        m_forceCheckForPaintInvalidation = false;

[Julien - ping for review, 2014/08/01 21:20:01]

Let's add a comment about why we clear the flag as it could be difficult to
remember the reason later on.

[abarth-chromium, 2014/08/01 21:22:51]

Ok.

+    } else {
         if (!renderer.supportsLayoutStateCachedOffsets() || !next.m_cachedOffsetsEnabled) {
             m_cachedOffsetsEnabled = false;
         } else if (m_cachedOffsetsEnabled) {
             m_paintOffset = next.m_paintOffset;
             // Handle relative positioned inline.
             if (renderer.style()->hasInFlowPosition() && renderer.layer())
                 m_paintOffset += renderer.layer()->offsetForInFlowPosition();
 
             // RenderInline can't be out-of-flow positioned.
         }
 
         // The following can't apply to RenderInline so we just propagate them.
         m_clipped = next.m_clipped;
         m_clipRect = next.m_clipRect;
     }
 }
 
 PaintInvalidationState::PaintInvalidationState(const PaintInvalidationState& next, RenderBox& renderer, const RenderLayerModelObject& paintInvalidationContainer)
     : m_clipped(false)
     , m_cachedOffsetsEnabled(true)
+    , m_forceCheckForPaintInvalidation(next.m_forceCheckForPaintInvalidation)
     , m_paintInvalidationContainer(paintInvalidationContainer)
     , m_renderer(renderer)
 {
     bool establishesPaintInvalidationContainer = &m_renderer == &m_paintInvalidationContainer;
     bool fixed = m_renderer.isOutOfFlowPositioned() && m_renderer.style()->position() == FixedPosition;
 
-    if (!establishesPaintInvalidationContainer) {
+    if (establishesPaintInvalidationContainer) {
+        m_forceCheckForPaintInvalidation = false;

[Julien - ping for review, 2014/08/01 21:20:01]

Ditto.

+    } else {
         if (!renderer.supportsLayoutStateCachedOffsets() || !next.m_cachedOffsetsEnabled) {
             m_cachedOffsetsEnabled = false;
         } else {
             LayoutSize offset = m_renderer.isTableRow() ? LayoutSize() : renderer.locationOffset();
             if (fixed) {
                 // FIXME: This doesn't work correctly with transforms.
                 FloatPoint fixedOffset = m_renderer.view()->localToAbsolute(FloatPoint(), IsFixed);
                 m_paintOffset = LayoutSize(fixedOffset.x(), fixedOffset.y()) + offset;
             } else {
                 m_paintOffset = next.m_paintOffset + offset;
@@ skipping 30 matching lines @@
     if (m_clipped) {
         m_clipRect.intersect(clipRect);
     } else {
         m_clipRect = clipRect;
         m_clipped = true;
     }
     m_paintOffset -= box.scrolledContentOffset();
 }
 
 } // namespace blink