Drop Chain.apply_transaction()

It was no longer used anywhere and it doesn't work because our VM is no
longer stateless

evm/chains/base.py

@@ -209,13 +209,6 @@ def get_vm(self, header=None):
     #
     # Execution API
     #
-    @abstractmethod
-    def apply_transaction(self, transaction):
-        """
-        Applies the transaction to the current head block of the Chain.
-        """
-        raise NotImplementedError("Chain classes must implement this method")
-
     @abstractmethod
     def estimate_gas(self, transaction, at_header=None):
         """
@@ -487,18 +480,6 @@ def from_genesis_header(cls, chaindb, genesis_header):
     #
     # Mining and Execution API
     #
-    def apply_transaction(self, transaction):
-        """
-        Applies the transaction to the current head block of the Chain.
-        """
-        vm = self.get_vm()
-        computation, block = vm.apply_transaction(transaction)
-
-        # Update header
-        self.header = block.header
-
-        return computation
-
     def estimate_gas(self, transaction, at_header=None):
         if at_header is None:
             at_header = self.get_canonical_head()

tests/core/chain-object/test_chain.py

@@ -34,17 +34,6 @@ def tx(chain, funded_address, funded_address_private_key):
     return new_transaction(vm, from_, recipient, amount, funded_address_private_key)
 
 
-def test_apply_transaction(chain, tx):
-    vm = chain.get_vm()
-
-    computation = chain.apply_transaction(tx)
-
-    # Check if the state is updated.
-    vm = chain.get_vm()
-    assert vm.state.state_root == computation.state.state_root
-    assert vm.state.read_only_state_db.get_balance(tx.to) == tx.value
-
-
 def test_import_block_validation(valid_chain, funded_address, funded_address_initial_balance):
     block = rlp.decode(valid_block_rlp, sedes=FrontierBlock)
     imported_block = valid_chain.import_block(block)