Move squash preventing reasons out of compositing reasons

third_party/WebKit/Source/core/paint/PaintLayer.h

Index: third_party/WebKit/Source/core/paint/PaintLayer.h
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.h b/third_party/WebKit/Source/core/paint/PaintLayer.h
index 3932a006ce92e9f3f11a1ed8cce432930cf27b5b..473f4583c086fff13d2dca5fc8ce5abccda588f6 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.h
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.h
@@ -57,6 +57,7 @@
 #include "core/paint/PaintLayerStackingNode.h"
 #include "core/paint/PaintLayerStackingNodeIterator.h"
 #include "platform/graphics/CompositingReasons.h"
+#include "platform/graphics/SquashingDisallowedReasons.h"
 #include "public/platform/WebBlendMode.h"
 #include "wtf/Allocator.h"
 #include "wtf/OwnPtr.h"
@@ -117,6 +118,10 @@ struct PaintLayerRareData {
     // Once computed, indicates all that a layer needs to become composited using the CompositingReasons enum bitfield.
     CompositingReasons compositingReasons;
 
+    // This captures reasons why a paint layer might be forced to be separately
+    // composited rather than sharing a backing with another layer.
+    SquashingDisallowedReasons squashingDisallowedReasons;
+
     // If the layer paints into its own backings, this keeps track of the backings.
     // It's nullptr if the layer is not composited or paints into grouped backing.
     OwnPtr<CompositedLayerMapping> compositedLayerMapping;
@@ -590,6 +595,9 @@ public:
     CompositingReasons compositingReasons() const { ASSERT(isAllowedToQueryCompositingState()); return m_rareData ? m_rareData->compositingReasons : CompositingReasonNone; }
     void setCompositingReasons(CompositingReasons, CompositingReasons mask = CompositingReasonAll);
 
+    SquashingDisallowedReasons squashingDisallowedReasons() const { ASSERT(isAllowedToQueryCompositingState()); return m_rareData ? m_rareData->squashingDisallowedReasons : SquashingDisallowedReasonsNone; }
+    void setSquashingDisallowedReasons(SquashingDisallowedReasons);
+
     bool hasCompositingDescendant() const { ASSERT(isAllowedToQueryCompositingState()); return m_hasCompositingDescendant; }
     void setHasCompositingDescendant(bool);