Remove zrxAssetData param to ensure that it is always in sync with zrxToken

contracts/staking/contracts/src/immutable/MixinConstants.sol

@@ -25,7 +25,7 @@ contract MixinConstants is
     MixinDeploymentConstants
 {
     // TODO: Reevaluate this variable
-    uint96 constant internal PERCENTAGE_DENOMINATOR = 100; // 10**18
+    uint8 constant internal PERCENTAGE_DENOMINATOR = 100;
 
     // The upper 16 bytes represent the pool id, so this would be pool id 1. See MixinStakinPool for more information.
     bytes32 constant internal INITIAL_POOL_ID = 0x0000000000000000000000000000000100000000000000000000000000000000;

contracts/staking/contracts/src/interfaces/IZrxVault.sol

@@ -54,12 +54,6 @@ interface IZrxVault {
         address erc20ProxyAddress
     );
 
-    /// @dev Emitted when the Zrx Asset Data is changed.
-    /// @param zrxAssetData New Zrx Asset Data. 
-    event ZrxAssetDataChanged(
-        bytes zrxAssetData
-    );
-
     /// @dev Sets the ERC20 proxy.
     /// Note that only the contract owner can call this.
     /// Note that this can only be called when *not* in Catastrophic Failure mode.
@@ -67,13 +61,6 @@ interface IZrxVault {
     function setErc20Proxy(address erc20ProxyAddress)
         external;
 
-    /// @dev Sets the Zrx Asset Data.
-    /// Note that only the contract owner can call this.
-    /// Note that this can only be called when *not* in Catastrophic Failure mode.
-    /// @param _zrxAssetData Zrx asset data for the ERC20 Proxy.
-    function setZrxAssetData(bytes calldata _zrxAssetData)
-        external;
-
     /// @dev Deposit an `amount` of Zrx Tokens from `owner` into the vault.
     /// Note that only the Staking contract can call this.
     /// Note that this can only be called when *not* in Catastrophic Failure mode.
@@ -90,7 +77,7 @@ interface IZrxVault {
     function withdrawFrom(address owner, uint256 amount)
         external;
 
-    /// @dev Withdraw ALL Zrx Tokens to `owner` from the vault.
+    /// @dev Withdraw all of sender's ZRX from vault from the vault.
     /// Note that this can only be called when *in* Catastrophic Failure mode.
     /// @param owner of Zrx Tokens.
     function withdrawAllFrom(address owner)

contracts/staking/contracts/src/vaults/ZrxVault.sol

@@ -21,6 +21,7 @@ pragma solidity ^0.5.9;
 import "../interfaces/IZrxVault.sol";
 import "@0x/contracts-utils/contracts/src/LibSafeMath.sol";
 import "@0x/contracts-asset-proxy/contracts/src/interfaces/IAssetProxy.sol";
+import "@0x/contracts-asset-proxy/contracts/src/interfaces/IAssetData.sol";
 import "@0x/contracts-erc20/contracts/src/interfaces/IERC20Token.sol";
 import "./MixinVaultCore.sol";
 
@@ -37,7 +38,6 @@ contract ZrxVault is
     IZrxVault,
     MixinVaultCore
 {
-
     using LibSafeMath for uint256;
 
     // mapping from Owner to ZRX balance
@@ -55,17 +55,18 @@ contract ZrxVault is
     /// @dev Constructor.
     /// @param erc20ProxyAddress Address of the 0x ERC20 Proxy.
     /// @param zrxTokenAddress Address of the Zrx Token.
-    /// @param _zrxAssetData Zrx asset data for the ERC20 Proxy.
     constructor(
         address erc20ProxyAddress,
-        address zrxTokenAddress,
+        address zrxTokenAddress
-        bytes memory _zrxAssetData
     )
         public
     {
         erc20Proxy = IAssetProxy(erc20ProxyAddress);
         zrxToken = IERC20Token(zrxTokenAddress);
-        zrxAssetData = _zrxAssetData;
+        zrxAssetData = abi.encodeWithSelector(
+            IAssetData(address(0)).ERC20Token.selector,
+            zrxTokenAddress
+        );
     }
 
     /// @dev Sets the ERC20 proxy.
@@ -81,19 +82,6 @@ contract ZrxVault is
         emit Erc20ProxyChanged(erc20ProxyAddress);
     }
 
-    /// @dev Sets the Zrx Asset Data.
-    /// Note that only the contract owner can call this.
-    /// Note that this can only be called when *not* in Catastrophic Failure mode.
-    /// @param _zrxAssetData Zrx asset data for the ERC20 Proxy.
-    function setZrxAssetData(bytes calldata _zrxAssetData)
-        external
-        onlyOwner
-        onlyNotInCatastrophicFailure
-    {
-        zrxAssetData = _zrxAssetData;
-        emit ZrxAssetDataChanged(_zrxAssetData);
-    }
-
     /// @dev Deposit an `amount` of Zrx Tokens from `owner` into the vault.
     /// Note that only the Staking contract can call this.
     /// Note that this can only be called when *not* in Catastrophic Failure mode.
@@ -132,7 +120,7 @@ contract ZrxVault is
         _withdrawFrom(owner, amount);
     }
 
-    /// @dev Withdraw ALL Zrx Tokens to `owner` from the vault.
+    /// @dev Withdraw all of sender's ZRX from vault from the vault.
     /// Note that this can only be called when *in* Catastrophic Failure mode.
     /// @param owner of Zrx Tokens.
     function withdrawAllFrom(address owner)

contracts/staking/test/utils/staking_wrapper.ts

@@ -1,7 +1,6 @@
 import { ERC20ProxyContract } from '@0x/contracts-asset-proxy';
 import { artifacts as erc20Artifacts, DummyERC20TokenContract } from '@0x/contracts-erc20';
 import { constants as testUtilsConstants, LogDecoder, txDefaults } from '@0x/contracts-test-utils';
-import { assetDataUtils } from '@0x/order-utils';
 import { SignatureType } from '@0x/types';
 import { BigNumber, logUtils } from '@0x/utils';
 import { Web3Wrapper } from '@0x/web3-wrapper';
@@ -100,7 +99,6 @@ export class StakingWrapper {
     }
     public async deployAndConfigureContractsAsync(): Promise<void> {
         // deploy zrx vault
-        const zrxAssetData = assetDataUtils.encodeERC20AssetData(this._zrxTokenContract.address);
         this._zrxVaultContractIfExists = await ZrxVaultContract.deployFrom0xArtifactAsync(
             artifacts.ZrxVault,
             this._provider,
@@ -108,7 +106,6 @@ export class StakingWrapper {
             artifacts,
             this._erc20ProxyContract.address,
             this._zrxTokenContract.address,
-            zrxAssetData,
         );
         // deploy reward vault
         this._rewardVaultContractIfExists = await StakingPoolRewardVaultContract.deployFrom0xArtifactAsync(