Move helper functions into DOM (#10051)

* Move helper functions into DOM

* Add tests and comments

src/sql/base/test/browser/dom.test.ts

@@ -0,0 +1,58 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as assert from 'assert';
+import { convertSize, convertSizeToNumber } from 'sql/base/browser/dom';
+
+suite('DOM Tests', () => {
+
+	test('Convert size should add px', () => {
+		const expected = '100px';
+		const actual = convertSize(100);
+		assert.equal(expected, actual);
+	});
+
+	test('Convert size should not add px if it already has it', () => {
+		const expected = '100px';
+		const actual = convertSize('100px');
+		assert.equal(expected, actual);
+	});
+
+	test('Convert size should not add px if it is a percent value', () => {
+		const expected = '100%';
+		const actual = convertSize('100%');
+		assert.equal(expected, actual);
+	});
+
+	test('Convert size should return the default value given undefined value', () => {
+		const expected = '200';
+		const actual = convertSize(undefined, '200');
+		assert.equal(expected, actual);
+	});
+
+	test('Convert to number should return size without px', () => {
+		const expected = 200;
+		const actual = convertSizeToNumber('200px');
+		assert.equal(expected, actual);
+	});
+
+	test('Convert to number should return same value if already plain text number', () => {
+		const expected = 200;
+		const actual = convertSizeToNumber('200');
+		assert.equal(expected, actual);
+	});
+
+	test('Convert to number should return same value if already plain number', () => {
+		const expected = 200;
+		const actual = convertSizeToNumber(200);
+		assert.equal(expected, actual);
+	});
+
+	test('Convert to number should return 0 given undefined', () => {
+		const expected = 0;
+		const actual = convertSizeToNumber(undefined);
+		assert.equal(expected, actual);
+	});
+});