Issue 5201 - [emscripten] Replace EM_ASM calls by a custom JavaScript library

compiled/subscription/DownloadableSubscription.h

Index: compiled/subscription/DownloadableSubscription.h
===================================================================
--- a/compiled/subscription/DownloadableSubscription.h
+++ b/compiled/subscription/DownloadableSubscription.h
@@ -12,17 +12,20 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #pragma once
 
+#include <cstdint>
+
 #include "Subscription.h"
+#include "../bindings/runtime.h"
 
 class DownloadableSubscription : public Subscription
 {
 public:
   explicit DownloadableSubscription(const String& id);
 
   SUBSCRIPTION_PROPERTY(bool, mFixedTitle, SUBSCRIPTION_FIXEDTITLE,
       GetFixedTitle, SetFixedTitle);
@@ -44,10 +47,10 @@ public:
       GetErrorCount, SetErrorCount);
   SUBSCRIPTION_PROPERTY(uint64_t, mDataRevision, NONE,
       GetDataRevision, SetDataRevision);
   SUBSCRIPTION_STRING_PROPERTY(mRequiredVersion, NONE,
       GetRequiredVersion, SetRequiredVersion);
   SUBSCRIPTION_PROPERTY(int, mDownloadCount, NONE,
       GetDownloadCount, SetDownloadCount);
 
-  EMSCRIPTEN_KEEPALIVE OwnedString Serialize() const;
+  BINDINGS_EXPORTED OwnedString Serialize() const;
 };