Bug 1522830: Part 4 - Add constexpr constructor and assignment operator from uint64_t to ModuleVersion; r=mhowell

Differential Revision: https://phabricator.services.mozilla.com/D53676

--HG--
extra : moz-landing-system : lando

widget/windows/WinHeaderOnlyUtils.h

@@ -526,6 +526,8 @@ inline UniquePtr<wchar_t[]> GetFullBinaryPath() {
 
 class ModuleVersion final {
  public:
+  constexpr ModuleVersion() : mVersion(0ULL) {}
+
   explicit ModuleVersion(const VS_FIXEDFILEINFO& aFixedInfo)
       : mVersion((static_cast<uint64_t>(aFixedInfo.dwFileVersionMS) << 32) |
                  static_cast<uint64_t>(aFixedInfo.dwFileVersionLS)) {}
@@ -555,6 +557,11 @@ class ModuleVersion final {
 
   bool operator<(const uint64_t& aOther) const { return mVersion < aOther; }
 
+  ModuleVersion& operator=(const uint64_t aIntVersion) {
+    mVersion = aIntVersion;
+    return *this;
+  }
+
  private:
   uint64_t mVersion;
 };