Remove OwnPtr from Blink.

third_party/WebKit/Source/core/html/canvas/CanvasFontCache.h

Index: third_party/WebKit/Source/core/html/canvas/CanvasFontCache.h
diff --git a/third_party/WebKit/Source/core/html/canvas/CanvasFontCache.h b/third_party/WebKit/Source/core/html/canvas/CanvasFontCache.h
index 47fc9125db13da83a8816c4a78d9a5a90c413079..f17c62041fc5d78f3d59c11d19b132eb924fbc0d 100644
--- a/third_party/WebKit/Source/core/html/canvas/CanvasFontCache.h
+++ b/third_party/WebKit/Source/core/html/canvas/CanvasFontCache.h
@@ -13,6 +13,7 @@
 #include "wtf/HashMap.h"
 #include "wtf/ListHashSet.h"
 #include "wtf/text/WTFString.h"
+#include <memory>
 
 namespace blink {
 
@@ -55,7 +56,7 @@ private:
     HashMap<String, Font> m_fontsResolvedUsingDefaultStyle;
     MutableStylePropertyMap m_fetchedFonts;
     ListHashSet<String> m_fontLRUList;
-    OwnPtr<FontCachePurgePreventer> m_mainCachePurgePreventer;
+    std::unique_ptr<FontCachePurgePreventer> m_mainCachePurgePreventer;
     Member<Document> m_document;
     RefPtr<ComputedStyle> m_defaultFontStyle;
     bool m_pruningScheduled;