EDK: Remove MOJO_SYSTEM_IMPL_EXPORT, system_impl_export.h, etc.

mojo/edk/system/master_connection_manager.h

Index: mojo/edk/system/master_connection_manager.h
diff --git a/mojo/edk/system/master_connection_manager.h b/mojo/edk/system/master_connection_manager.h
index 091d009ad9b161cf5d1198c1958ce57b1bc7ce85..97fb8ee561a9ee33d2e869dda45da168a5d300e4 100644
--- a/mojo/edk/system/master_connection_manager.h
+++ b/mojo/edk/system/master_connection_manager.h
@@ -14,7 +14,6 @@
 #include "mojo/edk/embedder/scoped_platform_handle.h"
 #include "mojo/edk/system/connection_manager.h"
 #include "mojo/edk/system/mutex.h"
-#include "mojo/edk/system/system_impl_export.h"
 #include "mojo/public/cpp/system/macros.h"
 
 namespace base {
@@ -37,8 +36,7 @@ namespace system {
 // its internal, private thread), with condition that |Init()| be called before
 // anything else and |Shutdown()| be called before destruction (and no other
 // public methods may be called during/after |Shutdown()|).
-class MOJO_SYSTEM_IMPL_EXPORT MasterConnectionManager final
-    : public ConnectionManager {
+class MasterConnectionManager final : public ConnectionManager {
  public:
   // Note: None of the public methods may be called from |private_thread_|.