Light friendly dapps (#5634)

* move native_contracts ABIs to JSON files, add urlhint

* port hash-fetch to futures, fix tests

* fix dapps compilation, defer async port to later

* activate dapps server in the light client

* better formatting

dapps/src/tests/fetch.rs

@@ -60,7 +60,7 @@ fn should_return_503_when_syncing_but_should_make_the_calls() {
 
 	// then
 	response.assert_status("HTTP/1.1 503 Service Unavailable");
-	assert_eq!(registrar.calls.lock().len(), 4);
+	assert_eq!(registrar.calls.lock().len(), 2);
 	assert_security_headers_for_embed(&response.headers);
 }
 

dapps/src/tests/helpers/registrar.rs

@@ -64,9 +64,10 @@ impl ContractClient for FakeRegistrar {
 		Ok(REGISTRAR.parse().unwrap())
 	}
 
-	fn call(&self, address: Address, data: Bytes) -> Result<Bytes, String> {
+	fn call(&self, address: Address, data: Bytes) -> ::futures::BoxFuture<Bytes, String> {
 		let call = (address.to_hex(), data.to_hex());
 		self.calls.lock().push(call.clone());
-		self.responses.lock().get(&call).cloned().expect(&format!("No response for call: {:?}", call))
+		let res = self.responses.lock().get(&call).cloned().expect(&format!("No response for call: {:?}", call));
+		Box::new(::futures::future::done(res))
 	}
 }