fix(aws-s3): remove bucket name validation (#628)

Now that Tokens can be stringified, they can be inserted into parameters
like `bucketName`, which can lead to an input string like
`"bucket-name-${Token[TOKEN.0]}"`. We can't properly validate these
strings anymore.

Fixes #624.

packages/@aws-cdk/aws-s3/lib/bucket.ts

@@ -9,7 +9,7 @@ import perms = require('./perms');
 import { CommonPipelineSourceProps, PipelineSource } from './pipeline-action';
 import { LifecycleRule } from './rule';
 import { BucketArn, BucketDomainName, BucketDualStackDomainName, BucketName, cloudformation } from './s3.generated';
-import { parseBucketArn, parseBucketName, validateBucketName } from './util';
+import { parseBucketArn, parseBucketName } from './util';
 
 /**
  * A reference to a bucket. The easiest way to instantiate is to call
@@ -367,8 +367,6 @@ export class Bucket extends BucketRef {
     constructor(parent: cdk.Construct, name: string, props: BucketProps = {}) {
         super(parent, name);
 
-        validateBucketName(props && props.bucketName);
-
         const { bucketEncryption, encryptionKey } = this.parseEncryption(props);
 
         const resource = new cloudformation.BucketResource(this, 'Resource', {

packages/@aws-cdk/aws-s3/lib/util.ts

@@ -1,16 +1,6 @@
 import { Arn } from '@aws-cdk/cdk';
 import { BucketRefProps } from './bucket';
 
-export function validateBucketName(bucketName?: string) {
-    if (!bucketName) {
-        return;
-    }
-
-    if (bucketName.search(/[^a-z0-9.-]/g) !== -1) {
-        throw new Error('Bucket name contains invalid characters: ' + bucketName);
-    }
-}
-
 export function parseBucketArn(props: BucketRefProps) {
 
     // if we have an explicit bucket ARN, use it.