Move scanner into pkg/front_end/lib/src/scanner.

pkg/analyzer/lib/src/dart/scanner/reader.dart

Index: pkg/analyzer/lib/src/dart/scanner/reader.dart
diff --git a/pkg/analyzer/lib/src/dart/scanner/reader.dart b/pkg/analyzer/lib/src/dart/scanner/reader.dart
index 81f506e09483a188e35d58a9be806e7578ee7879..54f367b05af2de2b2802738541edd5eeff6b37e6 100644
--- a/pkg/analyzer/lib/src/dart/scanner/reader.dart
+++ b/pkg/analyzer/lib/src/dart/scanner/reader.dart
@@ -4,6 +4,10 @@
 
 library analyzer.src.dart.scanner.reader;
 
+import 'package:front_end/src/scanner/reader.dart';
+
+export 'package:front_end/src/scanner/reader.dart' show CharacterReader;
+
 /**
  * A [CharacterReader] that reads a range of characters from another character
  * reader.
@@ -57,47 +61,6 @@ class CharacterRangeReader extends CharacterReader {
 }
 
 /**
- * An object used by the scanner to read the characters to be scanned.
- */
-abstract class CharacterReader {
-  /**
-   * The current offset relative to the beginning of the source. Return the
-   * initial offset if the scanner has not yet scanned the source code, and one
-   * (1) past the end of the source code if the entire source code has been
-   * scanned.
-   */
-  int get offset;
-
-  /**
-   * Set the current offset relative to the beginning of the source to the given
-   * [offset]. The new offset must be between the initial offset and one (1)
-   * past the end of the source code.
-   */
-  void set offset(int offset);
-
-  /**
-   * Advance the current position and return the character at the new current
-   * position.
-   */
-  int advance();
-
-  /**
-   * Return the substring of the source code between the [start] offset and the
-   * modified current position. The current position is modified by adding the
-   * [endDelta], which is the number of characters after the current location to
-   * be included in the string, or the number of characters before the current
-   * location to be excluded if the offset is negative.
-   */
-  String getString(int start, int endDelta);
-
-  /**
-   * Return the character at the current position without changing the current
-   * position.
-   */
-  int peek();
-}
-
-/**
  * A [CharacterReader] that reads characters from a character sequence.
  */
 class CharSequenceReader implements CharacterReader {