Only record one in n line endings to save space.

test/mjsunit/debug-sourceinfo.js

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 45 matching lines @@
 }
 
 // Get the Debug object exposed from the debug context global object.
 Debug = debug.Debug
 
 // This is the number of comment lines above the first test function.
 var comment_lines = 28;
 
 // This is the last position in the entire file (note: this equals
 // file size of <debug-sourceinfo.js> - 1, since starting at 0).
-var last_position = 11337;
+var last_position = 11591;
 // This is the last line of entire file (note: starting at 0).
-var last_line = 265;
-// This is the last column of last line (note: starting at 0 and +1, due
-// to trailing <LF>).
+var last_line = 268;
+// This is the column of the last character (note: starting at 0) due to
+// final line having a trailing newline that is conceptually part of that line.
 var last_column = 1;
 
 // This magic number is the length or the first line comment (actually number
 // of characters before 'function a(...'.
 var comment_line_length = 1633;
 var start_a = 9 + comment_line_length;
 var start_b = 35 + comment_line_length;
 var start_c = 66 + comment_line_length;
 var start_d = 151 + comment_line_length;
 
@@ skipping 162 matching lines @@
 assertEquals(70 + start_c, Debug.findFunctionSourceLocation(c, 6, 0).position);
 assertEquals(0 + start_d, Debug.findFunctionSourceLocation(d, 0, 0).position);
 assertEquals(6 + start_d, Debug.findFunctionSourceLocation(d, 1, 0).position);
 for (i = 1; i <= num_lines_d; i++) {
   assertEquals(6 + (i * line_length_d) + start_d, Debug.findFunctionSourceLocation(d, (i + 1), 0).position);
 }
 assertEquals(158 + start_d, Debug.findFunctionSourceLocation(d, 17, 0).position);
 
 // Make sure invalid inputs work properly.
 assertEquals(0, script.locationFromPosition(-1).line);
-assertEquals(null, script.locationFromPosition(last_position + 1));
+// We might expect last_position + 1 to be the first illegal position, but we
+// sometimes generate character positions that are one past the last character.
+// See Rewriter::Rewrite for details.
+assertEquals(null, script.locationFromPosition(last_position + 2));
 
 // Test last position.
 assertEquals(last_position, script.locationFromPosition(last_position).position);
 assertEquals(last_line, script.locationFromPosition(last_position).line);
 assertEquals(last_column, script.locationFromPosition(last_position).column);
 
 // Test that script.sourceLine(line) works.
 var location;
 
 for (line = 0; line < num_lines_d; line++) {
   var line_content_regexp = new RegExp("  x = " + (line + 1));
   assertTrue(line_content_regexp.test(script.sourceLine(start_line_d + line)));
 }