Allow OSExchangeData::Provider to be overridden at run time.

ui/base/dragdrop/os_exchange_data.h

Index: ui/base/dragdrop/os_exchange_data.h
diff --git a/ui/base/dragdrop/os_exchange_data.h b/ui/base/dragdrop/os_exchange_data.h
index e7890258dc8a5d3e861964e1485ef0cb8ab916e0..683197de275155f86cc1006e2747d221abd83d19 100644
--- a/ui/base/dragdrop/os_exchange_data.h
+++ b/ui/base/dragdrop/os_exchange_data.h
@@ -87,7 +87,7 @@ class UI_BASE_EXPORT OSExchangeData {
     Provider() {}
     virtual ~Provider() {}
 
-    virtual Provider* Clone() const = 0;
+    virtual std::unique_ptr<Provider> Clone() const = 0;
 
     virtual void MarkOriginatedFromRenderer() = 0;
     virtual bool DidOriginateFromRenderer() const = 0;
@@ -138,13 +138,10 @@ class UI_BASE_EXPORT OSExchangeData {
 #endif
   };
 
-  // Creates the platform specific Provider.
-  static Provider* CreateProvider();
-
   OSExchangeData();
   // Creates an OSExchangeData with the specified provider. OSExchangeData
   // takes ownership of the supplied provider.
-  explicit OSExchangeData(Provider* provider);
+  explicit OSExchangeData(std::unique_ptr<Provider> provider);
 
   ~OSExchangeData();