[views-mus] Prevent creating a native OzonePlatform in mus tests.

ui/base/dragdrop/os_exchange_data_provider_factory.h

Index: ui/base/dragdrop/os_exchange_data_provider_factory.h
diff --git a/ui/base/dragdrop/os_exchange_data_provider_factory.h b/ui/base/dragdrop/os_exchange_data_provider_factory.h
index 423c70014cf12e85bc663dba665f039bc72275ad..4029d089f623f889fba9c5f51e4cae471f51085f 100644
--- a/ui/base/dragdrop/os_exchange_data_provider_factory.h
+++ b/ui/base/dragdrop/os_exchange_data_provider_factory.h
@@ -25,6 +25,9 @@ class UI_BASE_EXPORT OSExchangeDataProviderFactory {
   // Sets the factory which builds the providers.
   static void SetFactory(Factory* factory);
 
+  // Returns the current factory and sets the factory to null.
+  static Factory* TakeFactory();

[sky, 2017/04/12 19:38:15]

Can this return a std::unique_ptr?

[Elliot Glaysher, 2017/04/12 19:52:25]

Not easily without changing the ownership the Factory, which in all cases I know
about is an object with its own ownership semantics.

+
   // Creates a Provider based on the current configuration.
   static std::unique_ptr<OSExchangeData::Provider> CreateProvider();
 };