Alternate way to track first paint

Source/core/rendering/RenderObject.h

Index: Source/core/rendering/RenderObject.h
diff --git a/Source/core/rendering/RenderObject.h b/Source/core/rendering/RenderObject.h
index f28fedfd783af02831e7a58a00040231eb7f4f93..5bd4b91aefb59054a88974c6302d19509b524812 100644
--- a/Source/core/rendering/RenderObject.h
+++ b/Source/core/rendering/RenderObject.h
@@ -117,6 +117,7 @@ enum InvalidationReason {
     InvalidationScroll,
     InvalidationSelection,
     InvalidationLayer,
+    InvalidationRendererInsertion,
     InvalidationRendererRemoval,
     InvalidationPaintRectangle
 };
@@ -833,9 +834,6 @@ public:
 
     void getTextDecorations(unsigned decorations, AppliedTextDecoration& underline, AppliedTextDecoration& overline, AppliedTextDecoration& linethrough, bool quirksMode = false, bool firstlineStyle = false);
 
-    void setHadPaintInvalidation();
-    bool hadPaintInvalidation() const;
-
     // Return the RenderLayerModelObject in the container chain which is responsible for painting this object, or 0
     // if painting is root-relative. This is the container that should be passed to the 'forPaintInvalidation'
     // methods.
@@ -1017,8 +1015,9 @@ public:
     const LayoutPoint& previousPositionFromPaintInvalidationBacking() const { return m_previousPositionFromPaintInvalidationBacking; }
     void setPreviousPositionFromPaintInvalidationBacking(const LayoutPoint& positionFromPaintInvalidationBacking) { m_previousPositionFromPaintInvalidationBacking = positionFromPaintInvalidationBacking; }
 
-    bool shouldDoFullPaintInvalidation() const { return m_bitfields.shouldDoFullPaintInvalidation(); }
+    bool shouldDoFullPaintInvalidation() const { return m_bitfields.fullPaintInvalidationReason() != InvalidationNone; }
     void setShouldDoFullPaintInvalidation(bool, MarkingBehavior = MarkContainingBlockChain);
+    void setShouldDoFullPaintInvalidationWithReason(InvalidationReason = InvalidationFull, MarkingBehavior = MarkContainingBlockChain);

[Julien - ping for review, 2014/09/26 17:56:24]

I don't think the default InvalidationReason is giving us much here. On the
contrary, it makes the code less readable.

It seems really weird that you could call
setShouldDoFullPaintInvalidationWithReason(InvalidationNone). I was going to
advise to just rename it to setShouldPaintInvalidationWithReason and drop the
incremental ASSERT that I find artificial, but we would run into inconsistencies
with the rest of the full-invalidation code.

Arguably we could remove the default MarkingBehavior but that's more like a nit
as it's not as bad as the InvalidationReason.

[Xianzhu, 2014/09/26 18:36:21]

- Removed the default value for InvalidationReason;
- In the function, asserts only full paint invalidation reasons are allowed.
- No more setShouldDoFullPaintInvalidationWithReason(InvalidationNone).

 
     bool shouldInvalidateOverflowForPaint() const { return m_bitfields.shouldInvalidateOverflowForPaint(); }
 
@@ -1200,7 +1199,6 @@ private:
     public:
         RenderObjectBitfields(Node* node)
             : m_selfNeedsLayout(false)
-            , m_shouldDoFullPaintInvalidation(false)
             , m_shouldInvalidateOverflowForPaint(false)
             , m_shouldDoFullPaintInvalidationIfSelfPaintingLayer(false)
             // FIXME: We should remove mayNeedPaintInvalidation once we are able to
@@ -1239,12 +1237,12 @@ private:
             , m_selectionState(SelectionNone)
             , m_flowThreadState(NotInsideFlowThread)
             , m_boxDecorationBackgroundState(NoBoxDecorationBackground)
+            , m_fullPaintInvalidationReason(InvalidationNone)
         {
         }
 
         // 32 bits have been used in the first word, and 11 in the second.

[Julien - ping for review, 2014/09/26 17:56:24]

Let's update the number of remaining bits please!

[Xianzhu, 2014/09/26 18:36:21]

Done.

         ADD_BOOLEAN_BITFIELD(selfNeedsLayout, SelfNeedsLayout);
-        ADD_BOOLEAN_BITFIELD(shouldDoFullPaintInvalidation, ShouldDoFullPaintInvalidation);
         ADD_BOOLEAN_BITFIELD(shouldInvalidateOverflowForPaint, ShouldInvalidateOverflowForPaint);
         ADD_BOOLEAN_BITFIELD(shouldDoFullPaintInvalidationIfSelfPaintingLayer, ShouldDoFullPaintInvalidationIfSelfPaintingLayer);
         ADD_BOOLEAN_BITFIELD(mayNeedPaintInvalidation, MayNeedPaintInvalidation);
@@ -1292,6 +1290,7 @@ private:
         unsigned m_selectionState : 3; // SelectionState
         unsigned m_flowThreadState : 2; // FlowThreadState
         unsigned m_boxDecorationBackgroundState : 2; // BoxDecorationBackgroundState
+        unsigned m_fullPaintInvalidationReason : 4; // InvalidationReason
 
     public:
         bool isOutOfFlowPositioned() const { return m_positionedState == IsOutOfFlowPositioned; }
@@ -1313,6 +1312,13 @@ private:
 
         ALWAYS_INLINE BoxDecorationBackgroundState boxDecorationBackgroundState() const { return static_cast<BoxDecorationBackgroundState>(m_boxDecorationBackgroundState); }
         ALWAYS_INLINE void setBoxDecorationBackgroundState(BoxDecorationBackgroundState s) { m_boxDecorationBackgroundState = s; }
+
+        InvalidationReason fullPaintInvalidationReason() const { return static_cast<InvalidationReason>(m_fullPaintInvalidationReason); }
+        void setFullPaintInvalidationReason(InvalidationReason reason)
+        {
+            ASSERT(reason != InvalidationIncremental);
+            m_fullPaintInvalidationReason = reason;
+        }
     };
 
 #undef ADD_BOOLEAN_BITFIELD