Blimp: relocate thread-unsafe member getter in DropConnection code.

blimp/client/core/blimp_client_context_impl.h

Index: blimp/client/core/blimp_client_context_impl.h
diff --git a/blimp/client/core/blimp_client_context_impl.h b/blimp/client/core/blimp_client_context_impl.h
index d2053ece2a87afa2dc6c661c8a0fe9efda0d35a4..8ee0f2a3027965c1e8dcc8724f157c20b086b2cd 100644
--- a/blimp/client/core/blimp_client_context_impl.h
+++ b/blimp/client/core/blimp_client_context_impl.h
@@ -84,6 +84,10 @@ class BlimpClientContextImpl
   void RegisterFeatures();
   void InitializeSettings();
 
+  // Terminates the active connection held by |net_connections_|.
+  // May be called on any thread.
+  void DropConnection();
+
   // Create IdentitySource which provides user sign in states and OAuth2 token
   // service.
   void CreateIdentitySource();