[mojo] Move NullAssociated{Receiver,Remote} into the correct header.

These are helpers for PendingAssociated{Receiver,Remote}, so they
should be defined in the corresponding header.

Bug: 1074391
Change-Id: If79abeecd90a5f3df5f5698181dccf2295aadabe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2165707
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Oksana Zhuravlova <oksamyt@chromium.org>
Auto-Submit: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Oksana Zhuravlova <oksamyt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762507}

mojo/public/cpp/bindings/associated_receiver.h

@@ -217,16 +217,6 @@ class AssociatedReceiver {
   DISALLOW_COPY_AND_ASSIGN(AssociatedReceiver);
 };
 
-// Constructs an invalid PendingAssociatedReceiver of any arbitrary interface
-// type. Useful as short-hand for a default constructed value.
-class COMPONENT_EXPORT(MOJO_CPP_BINDINGS) NullAssociatedReceiver {
- public:
-  template <typename Interface>
-  operator PendingAssociatedReceiver<Interface>() const {
-    return PendingAssociatedReceiver<Interface>();
-  }
-};
-
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_ASSOCIATED_RECEIVER_H_

mojo/public/cpp/bindings/associated_remote.h

@@ -277,16 +277,6 @@ class AssociatedRemote {
   DISALLOW_COPY_AND_ASSIGN(AssociatedRemote);
 };
 
-// Constructs an invalid PendingAssociatedRemote of any arbitrary interface
-// type. Useful as short-hand for a default constructed value.
-class COMPONENT_EXPORT(MOJO_CPP_BINDINGS) NullAssociatedRemote {
- public:
-  template <typename Interface>
-  operator PendingAssociatedRemote<Interface>() const {
-    return PendingAssociatedRemote<Interface>();
-  }
-};
-
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_ASSOCIATED_REMOTE_H_

mojo/public/cpp/bindings/pending_associated_receiver.h

@@ -91,6 +91,16 @@ class PendingAssociatedReceiver {
   DISALLOW_COPY_AND_ASSIGN(PendingAssociatedReceiver);
 };
 
+// Constructs an invalid PendingAssociatedReceiver of any arbitrary interface
+// type. Useful as short-hand for a default constructed value.
+class COMPONENT_EXPORT(MOJO_CPP_BINDINGS) NullAssociatedReceiver {
+ public:
+  template <typename Interface>
+  operator PendingAssociatedReceiver<Interface>() const {
+    return PendingAssociatedReceiver<Interface>();
+  }
+};
+
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_PENDING_ASSOCIATED_RECEIVER_H_

mojo/public/cpp/bindings/pending_associated_remote.h

@@ -97,6 +97,16 @@ class PendingAssociatedRemote {
   DISALLOW_COPY_AND_ASSIGN(PendingAssociatedRemote);
 };
 
+// Constructs an invalid PendingAssociatedRemote of any arbitrary interface
+// type. Useful as short-hand for a default constructed value.
+class COMPONENT_EXPORT(MOJO_CPP_BINDINGS) NullAssociatedRemote {
+ public:
+  template <typename Interface>
+  operator PendingAssociatedRemote<Interface>() const {
+    return PendingAssociatedRemote<Interface>();
+  }
+};
+
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_PENDING_ASSOCIATED_REMOTE_H_