Add LayoutObject::RarePaintData for rare paint data

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  *               (http://www.torchmobile.com/)
@@ skipping 108 matching lines @@
   virtual ~SameSizeAsLayoutObject() {}  // Allocate vtable pointer.
   void* pointers[5];
   Member<void*> members[1];
 #if DCHECK_IS_ON()
   unsigned m_debugBitfields : 2;
 #endif
   unsigned m_bitfields;
   unsigned m_bitfields2;
   LayoutRect m_visualRect;
   LayoutPoint m_paintOffset;
-  std::unique_ptr<void*> m_paintProperties;
+  std::unique_ptr<void*> m_rarePaintData;
 };
 
 static_assert(sizeof(LayoutObject) == sizeof(SameSizeAsLayoutObject),
               "LayoutObject should stay small");
 
 bool LayoutObject::s_affectsParentBlock = false;
 
 void* LayoutObject::operator new(size_t sz) {
   ASSERT(isMainThread());
   return PartitionAlloc(WTF::Partitions::layoutPartition(), sz,
@@ skipping 3405 matching lines @@
       isBackgroundAttachmentFixedObject)
     return;
   m_bitfields.setIsBackgroundAttachmentFixedObject(
       isBackgroundAttachmentFixedObject);
   if (isBackgroundAttachmentFixedObject)
     frameView()->addBackgroundAttachmentFixedObject(this);
   else
     frameView()->removeBackgroundAttachmentFixedObject(this);
 }
 
-const ObjectPaintProperties* LayoutObject::paintProperties() const {
-  DCHECK(RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled());
-  return m_paintProperties.get();
+LayoutObject::RarePaintData::RarePaintData() {}

[Xianzhu, 2017/03/30 03:11:18]

Nit: I think we can just use the default constructor and constructor which are
inlined by default.

[pdr., 2017/03/30 18:57:33]

This does have to be here. Windows puts the default ctor in the header and we
don't have full type info for ObjectPaintProperties in the header.

The failure from commenting out this line is:
FAILED: blink_core.dll blink_core.dll.lib blink_core.dll.pdb
C:/python_27_amd64/files/python.exe ../../build/toolchain/win/tool_wrapper.py
link-wrapper environment.x86 False link.exe /nologo /IMPLIB:./blink_core.dll.lib
/DLL /OUT:./blin
k_core.dll /PDB:./blink_core.dll.pdb @./blink_core.dll.rsp
LayoutObject.obj : error LNK2019: unresolved external symbol "public: __thiscall
blink::LayoutObject::RarePaintData::RarePaintData(void)"
(??0RarePaintData@LayoutObject@blink@
@QAE@XZ) referenced in function "class std::unique_ptr<class
blink::LayoutObject::RarePaintData,struct std::default_delete<class
blink::LayoutObject::RarePaintData> > __cdecl
base::MakeUnique<class blink::LayoutObject::RarePaintData>(void)"
(??$MakeUnique@VRarePaintData@LayoutObject@blink@@$$V@base@@YA?AV?$unique_ptr@VRarePaintData@LayoutObject@bli
nk@@U?$default_delete@VRarePaintData@LayoutObject@blink@@@std@@@std@@XZ)
./blink_core.dll : fatal error LNK1120: 1 unresolved externals
ninja: build stopped: subcommand failed.

+
+LayoutObject::RarePaintData::~RarePaintData() {}
+
+ObjectPaintProperties& LayoutObject::RarePaintData::ensurePaintProperties() {
+  if (!m_paintProperties)
+    m_paintProperties = ObjectPaintProperties::create();
+  return *m_paintProperties.get();
 }
 
-ObjectPaintProperties& LayoutObject::ensurePaintProperties() {
-  DCHECK(RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled());
-  if (!m_paintProperties)
-    m_paintProperties = ObjectPaintProperties::create();
-  return *m_paintProperties;
+LayoutObject::RarePaintData& LayoutObject::ensureRarePaintData() {
+  if (!m_rarePaintData)
+    m_rarePaintData = WTF::makeUnique<RarePaintData>();
+  return *m_rarePaintData.get();
 }
 
 LayoutRect LayoutObject::debugRect() const {
   LayoutRect rect;
   LayoutBlock* block = containingBlock();
   if (block)
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
@@ skipping 51 matching lines @@
     const blink::LayoutObject* root = object1;
     while (root->parent())
       root = root->parent();
     root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
   } else {
     WTFLogAlways("%s", "Cannot showLayoutTree. Root is (nil)");
   }
 }
 
 #endif