Mojo C++ bindings: more consistent Clone() and Equals().

mojo/public/cpp/bindings/interface_request.h

Index: mojo/public/cpp/bindings/interface_request.h
diff --git a/mojo/public/cpp/bindings/interface_request.h b/mojo/public/cpp/bindings/interface_request.h
index 3d6b27c0a0ea976a09ca23207235b60911e393cf..26e7b53cdc1e514ec49c47bab4bb356db39e44a8 100644
--- a/mojo/public/cpp/bindings/interface_request.h
+++ b/mojo/public/cpp/bindings/interface_request.h
@@ -55,6 +55,15 @@ class InterfaceRequest {
   // Removes the message pipe from the request and returns it.
   ScopedMessagePipeHandle PassMessagePipe() { return std::move(handle_); }
 
+  bool Equals(const InterfaceRequest& other) const {
+    if (this == &other)
+      return true;
+
+    // Now that the two refer to different objects, they are equivalent if
+    // and only if they are both invalid.
+    return !is_pending() && !other.is_pending();
+  }
+
  private:
   ScopedMessagePipeHandle handle_;
 };