Improve handling of PaintInvalidationLayer (renamed to PaintInvalidationSubtree)

third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp

Index: third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp
diff --git a/third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp b/third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp
index 1b53e44ec460467725b8986801a9cf0ea4d389cf..1323ca74fe915460074f06a3189ef737011be8e4 100644
--- a/third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp
+++ b/third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp
@@ -29,8 +29,7 @@ static bool supportsCachedOffsets(const LayoutObject& object)
 
 PaintInvalidationState::PaintInvalidationState(const LayoutView& layoutView, Vector<LayoutObject*>& pendingDelayedPaintInvalidations)
     : m_currentObject(layoutView)
-    , m_forcedSubtreeInvalidationWithinContainer(false)
-    , m_forcedSubtreeInvalidationRectUpdateWithinContainer(false)
+    , m_forcedSubtreeInvalidationFlags(0)
     , m_clipped(false)
     , m_clippedForAbsolutePosition(false)
     , m_cachedOffsetsEnabled(true)
@@ -59,8 +58,7 @@ PaintInvalidationState::PaintInvalidationState(const LayoutView& layoutView, Vec
 
 PaintInvalidationState::PaintInvalidationState(const PaintInvalidationState& parentState, const LayoutObject& currentObject)
     : m_currentObject(currentObject)
-    , m_forcedSubtreeInvalidationWithinContainer(parentState.m_forcedSubtreeInvalidationWithinContainer)
-    , m_forcedSubtreeInvalidationRectUpdateWithinContainer(parentState.m_forcedSubtreeInvalidationRectUpdateWithinContainer)
+    , m_forcedSubtreeInvalidationFlags(parentState.m_forcedSubtreeInvalidationFlags)
     , m_clipped(parentState.m_clipped)
     , m_clippedForAbsolutePosition(parentState.m_clippedForAbsolutePosition)
     , m_clipRect(parentState.m_clipRect)
@@ -119,6 +117,8 @@ PaintInvalidationState::PaintInvalidationState(const PaintInvalidationState& par
         //   descendants if possible; or
         // - Track offset between the two paintInvalidationContainers.
         m_cachedOffsetsEnabled = false;
+        if (m_forcedSubtreeInvalidationFlags & FullInvalidationForStackedContents)
+            m_forcedSubtreeInvalidationFlags |= FullInvalidation;
     }
 
     if (!currentObject.isBoxModelObject() && !currentObject.isSVG())
@@ -144,21 +144,25 @@ PaintInvalidationState::PaintInvalidationState(const PaintInvalidationState& par
         // continue forcing a check for paint invalidation, since we're
         // descending into a different invalidation container. (For instance if
         // our parents were moved, the entire container will just move.)
-        m_forcedSubtreeInvalidationWithinContainer = false;
-        m_forcedSubtreeInvalidationRectUpdateWithinContainer = false;
-
-        if (currentObject == m_paintInvalidationContainerForStackedContents
-            && currentObject != m_containerForAbsolutePosition
-            && m_cachedOffsetsForAbsolutePositionEnabled
-            && m_cachedOffsetsEnabled) {
-            // The current object is the new paintInvalidationContainer for absolute-position descendants but is not their container.
-            // Call updateForCurrentObject() before resetting m_paintOffset to get paint offset of the current object
-            // from the original paintInvalidationContainerForStackingContents, then use this paint offset to adjust
-            // m_paintOffsetForAbsolutePosition.
-            updateForCurrentObject(parentState);
-            m_paintOffsetForAbsolutePosition -= m_paintOffset;
-            if (m_clippedForAbsolutePosition)
-                m_clipRectForAbsolutePosition.move(-m_paintOffset);
+        // However, we need to keep the FullInvalidationForStackedContents flag
+        // if the current object isn't the paint invalidation container of
+        // stacked contents.
+        if (currentObject != m_paintInvalidationContainerForStackedContents) {
+            m_forcedSubtreeInvalidationFlags &= FullInvalidationForStackedContents;

[chrishtr, 2016/05/10 18:15:54]

|= instead of &= ?

[Xianzhu, 2016/05/10 19:09:20]

No. This is to clear other flags just keeping FullInvalidationForStackedContents
if it's set because the new paint invalidation container doesn't establish paint
invalidation container for stacked contents.

Moved the comment at 147-149 into the block.

+        } else {
+            m_forcedSubtreeInvalidationFlags = 0;
+            if (currentObject != m_containerForAbsolutePosition
+                && m_cachedOffsetsForAbsolutePositionEnabled
+                && m_cachedOffsetsEnabled) {
+                // The current object is the new paintInvalidationContainer for absolute-position descendants but is not their container.
+                // Call updateForCurrentObject() before resetting m_paintOffset to get paint offset of the current object
+                // from the original paintInvalidationContainerForStackingContents, then use this paint offset to adjust
+                // m_paintOffsetForAbsolutePosition.
+                updateForCurrentObject(parentState);
+                m_paintOffsetForAbsolutePosition -= m_paintOffset;
+                if (m_clippedForAbsolutePosition)
+                    m_clipRectForAbsolutePosition.move(-m_paintOffset);
+            }
         }
 
         m_clipped = false; // Will be updated in updateForChildren().
@@ -231,13 +235,27 @@ void PaintInvalidationState::updateForCurrentObject(const PaintInvalidationState
         m_paintOffset += toLayoutBoxModelObject(m_currentObject).layer()->offsetForInFlowPosition();
 }
 
-void PaintInvalidationState::updateForChildren()
+void PaintInvalidationState::updateForChildren(PaintInvalidationReason reason)
 {
 #if ENABLE(ASSERT)
     ASSERT(!m_didUpdateForChildren);
     m_didUpdateForChildren = true;
 #endif
 
+    switch (reason) {
+    case PaintInvalidationDelayedFull:
+        pushDelayedPaintInvalidationTarget(const_cast<LayoutObject&>(m_currentObject));
+        break;
+    case PaintInvalidationSubtree:
+        m_forcedSubtreeInvalidationFlags |= (FullInvalidation | FullInvalidationForStackedContents);
+        break;
+    case PaintInvalidationSVGResourceChange:
+        setForceSubtreeInvalidationCheckingWithinContainer();
+        break;
+    default:
+        break;
+    }
+
     updateForNormalChildren();
 
     if (m_currentObject == m_containerForAbsolutePosition) {