Add copy/move-ctor/operator for BrowserDMToken class

BrowserDMToken contains a string and an enum. It should be able to be
copied and moved as a normal string. Explicitly declare copy and move
constructor and operator.

Also move the factory function declaration to the top of the class.

Bug: 1020296
Change-Id: I401812b07db1bd2801a4133cb67592f9ef4bc6d2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1906477Reviewed-by: Roger Tawa <rogerta@chromium.org>
Commit-Queue: Owen Min <zmin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714515}

chrome/browser/policy/browser_dm_token_storage.cc

@@ -59,6 +59,17 @@ BrowserDMToken BrowserDMToken::CreateEmptyToken() {
   return BrowserDMToken(Status::kEmpty, "");
 }
 
+BrowserDMToken::BrowserDMToken(const BrowserDMToken& other) = default;
+
+BrowserDMToken::BrowserDMToken(BrowserDMToken&& other) = default;
+
+BrowserDMToken& BrowserDMToken::operator=(const BrowserDMToken& other) =
+    default;
+
+BrowserDMToken& BrowserDMToken::operator=(BrowserDMToken&& other) = default;
+
+BrowserDMToken::~BrowserDMToken() = default;
+
 const std::string& BrowserDMToken::value() const {
   // TODO(domfc): Uncomment DCHECK(is_valid()) after migrating code.
   // DCHECK(is_valid());

chrome/browser/policy/browser_dm_token_storage.h

@@ -44,16 +44,23 @@ class BrowserDMTokenStorage {
   //    enrollment token is present.
   class BrowserDMToken {
    public:
+    static BrowserDMToken CreateValidToken(const std::string& value);
+    static BrowserDMToken CreateInvalidToken();
+    static BrowserDMToken CreateEmptyToken();
+
+    BrowserDMToken(const BrowserDMToken& other);
+    BrowserDMToken(BrowserDMToken&& other);
+
+    BrowserDMToken& operator=(const BrowserDMToken& other);
+    BrowserDMToken& operator=(BrowserDMToken&& other);
+    ~BrowserDMToken();
+
     const std::string& value() const;
 
     bool is_valid() const;
     bool is_invalid() const;
     bool is_empty() const;
 
-    static BrowserDMToken CreateValidToken(const std::string& value);
-    static BrowserDMToken CreateInvalidToken();
-    static BrowserDMToken CreateEmptyToken();
-
    private:
     enum class Status { kValid, kInvalid, kEmpty };