Make DisplayItemClient an interface

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

Index: third_party/WebKit/Source/platform/graphics/paint/DisplayItem.h
diff --git a/third_party/WebKit/Source/platform/graphics/paint/DisplayItem.h b/third_party/WebKit/Source/platform/graphics/paint/DisplayItem.h
index 632fa11d2677a35c0755d2c8991722d5ed772cf4..4168d6d6c788de9ee48baf1ba9c37d3591a5103d 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/DisplayItem.h
+++ b/third_party/WebKit/Source/platform/graphics/paint/DisplayItem.h
@@ -192,8 +192,8 @@ public:
         TableCollapsedBorderLeft = 1 << 3,
     };
 
-    DisplayItem(const DisplayItemClientWrapper& client, Type type, size_t derivedSize)
-        : m_client(client.displayItemClient())
+    DisplayItem(const DisplayItemClient& client, Type type, size_t derivedSize)
+        : m_client(&client)
         , m_scope(0)
         , m_type(type)
         , m_derivedSize(derivedSize)
@@ -213,7 +213,7 @@ public:
     // Ids are for matching new DisplayItems with existing DisplayItems.
     struct Id {
         STACK_ALLOCATED();
-        Id(const DisplayItemClient client, const Type type, const unsigned scope)
+        Id(const DisplayItemClient& client, const Type type, const unsigned scope)
             : client(client)
             , type(type)
             , scope(scope) { }
@@ -223,12 +223,12 @@ public:
             // We should always convert to non-cached types before matching.
             ASSERT(!isCachedType(item.m_type));
             ASSERT(!isCachedType(type));
-            return client == item.m_client
+            return &client == item.m_client
                 && type == item.m_type
                 && scope == item.m_scope;
         }
 
-        const DisplayItemClient client;
+        const DisplayItemClient& client;
         const Type type;
         const unsigned scope;
     };
@@ -246,12 +246,12 @@ public:
     // Return the Id with cached type converted to non-cached type.
     Id nonCachedId() const
     {
-        return Id(m_client, nonCachedType(m_type), m_scope);
+        return Id(*m_client, nonCachedType(m_type), m_scope);
     }
 
     virtual void replay(GraphicsContext&) const { }
 
-    DisplayItemClient client() const { return m_client; }
+    const DisplayItemClient& client() const { ASSERT(m_client); return *m_client; }
     Type type() const { return m_type; }
 
     void setScope(unsigned scope) { m_scope = scope; }
@@ -345,7 +345,7 @@ public:
 
 #ifndef NDEBUG
     static WTF::String typeAsDebugString(DisplayItem::Type);
-    const WTF::String& clientDebugString() const { return m_clientDebugString; }
+    const WTF::String clientDebugString() const { return m_clientDebugString; }
     void setClientDebugString(const WTF::String& s) { m_clientDebugString = s; }
     WTF::String asDebugString() const;
     virtual void dumpPropertiesAsDebugString(WTF::StringBuilder&) const;
@@ -365,7 +365,7 @@ private:
         , m_skippedCache(false)
     { }
 
-    const DisplayItemClient m_client;
+    const DisplayItemClient* m_client;
     unsigned m_scope;
     static_assert(TypeLast < (1 << 16), "DisplayItem::Type should fit in 16 bits");
     const Type m_type : 16;
@@ -379,7 +379,7 @@ private:
 
 class PLATFORM_EXPORT PairedBeginDisplayItem : public DisplayItem {
 protected:
-    PairedBeginDisplayItem(const DisplayItemClientWrapper& client, Type type, size_t derivedSize) : DisplayItem(client, type, derivedSize) { }
+    PairedBeginDisplayItem(const DisplayItemClient& client, Type type, size_t derivedSize) : DisplayItem(client, type, derivedSize) { }
 
 private:
     bool isBegin() const final { return true; }
@@ -387,7 +387,7 @@ private:
 
 class PLATFORM_EXPORT PairedEndDisplayItem : public DisplayItem {
 protected:
-    PairedEndDisplayItem(const DisplayItemClientWrapper& client, Type type, size_t derivedSize) : DisplayItem(client, type, derivedSize) { }
+    PairedEndDisplayItem(const DisplayItemClient& client, Type type, size_t derivedSize) : DisplayItem(client, type, derivedSize) { }
 
 #if ENABLE(ASSERT)
     bool isEndAndPairedWith(DisplayItem::Type otherType) const override = 0;