fix(language-service): Preserve CRLF in templates for language-service (#33241)

This is a potential fix for https://github.com/angular/vscode-ng-language-service/issues/235
suggested by @andrius-pra in
47696136e3.

Currently, CRLF line endings are converted to LFs and this causes the
diagnostics span to be off in templates that use CRLF. The line endings
must be preserved in order to maintain correct span offset. The solution
is to add an option to the Tokenizer to indicate such preservation.

PR Close #33241

packages/compiler/src/ml_parser/lexer.ts

@@ -101,6 +101,10 @@ export interface TokenizeOptions {
    * included in source-map segments.  A common example is whitespace.
    */
   leadingTriviaChars?: string[];
+  /**
+   * If true, do not convert CRLF to LF.
+   */
+  preserveLineEndings?: boolean;
 }
 
 export function tokenize(
@@ -134,6 +138,7 @@ class _Tokenizer {
   private _currentTokenType: TokenType|null = null;
   private _expansionCaseStack: TokenType[] = [];
   private _inInterpolation: boolean = false;
+  private readonly _preserveLineEndings: boolean;
   tokens: Token[] = [];
   errors: TokenError[] = [];
 
@@ -153,6 +158,7 @@ class _Tokenizer {
         options.range || {endPos: _file.content.length, startPos: 0, startLine: 0, startCol: 0};
     this._cursor = options.escapedString ? new EscapedCharacterCursor(_file, range) :
                                            new PlainCharacterCursor(_file, range);
+    this._preserveLineEndings = options.preserveLineEndings || false;
     try {
       this._cursor.init();
     } catch (e) {
@@ -161,6 +167,9 @@ class _Tokenizer {
   }
 
   private _processCarriageReturns(content: string): string {
+    if (this._preserveLineEndings) {
+      return content;
+    }
     // http://www.w3.org/TR/html5/syntax.html#preprocessing-the-input-stream
     // In order to keep the original position in the source, we can not
     // pre-process it.