Create PaintChunk and begin writing code to build paint chunks.

third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.h

Index: third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.h
diff --git a/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.h b/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.h
index e4a0ab1f35d39d51ce278d56c312f4315719ca3f..81638e0c8bb28c7541150b0b6391d1ebdaf0c34b 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.h
+++ b/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.h
@@ -10,6 +10,8 @@
 #include "platform/geometry/LayoutPoint.h"
 #include "platform/graphics/ContiguousContainer.h"
 #include "platform/graphics/paint/DisplayItem.h"
+#include "platform/graphics/paint/PaintChunk.h"
+#include "platform/graphics/paint/PaintChunker.h"
 #include "platform/graphics/paint/Transform3DDisplayItem.h"
 #include "wtf/Alignment.h"
 #include "wtf/HashMap.h"
@@ -19,6 +21,8 @@
 
 namespace blink {
 
+class CachedDisplayItem;
+class DrawingDisplayItem;
 class GraphicsContext;
 
 // kDisplayItemAlignment must be a multiple of alignof(derived display item) for
@@ -76,6 +80,11 @@ public:
 #endif
 
     // These methods are called during painting.
+
+    // Provide a new set of paint properties to apply to recorded display items,
+    // for Slimming Paint v2.
+    void updateCurrentPaintProperties(const PaintProperties&);
+
     template <typename DisplayItemClass, typename... Args>
     DisplayItemClass& createAndAppend(Args&&... args)
     {
@@ -115,6 +124,9 @@ public:
     // Get the paint list generated after the last painting.
     const DisplayItems& displayItems() const;
 
+    // Get the paint chunks generated after the last painting.
+    const Vector<PaintChunk>& paintChunks() const;
+
     bool clientCacheIsValid(DisplayItemClient) const;
 
     // Commits the new display items and plays back the updated display items into the given context.
@@ -199,6 +211,12 @@ private:
     DisplayItems m_currentDisplayItems;
     DisplayItems m_newDisplayItems;
 
+    // In Slimming Paint v2, paint properties (e.g. transform) useful for
+    // compositing are stored in corresponding paint chunks instead of in the
+    // display items.
+    Vector<PaintChunk> m_currentPaintChunks;
+    PaintChunker m_newPaintChunks;
+
     // Contains all clients having valid cached paintings if updated.
     // It's lazily updated in updateValidlyCachedClientsIfNeeded().
     // FIXME: In the future we can replace this with client-side repaint flags