Add operators test to source_mapping_test.

tests/compiler/dart2js/sourcemaps/sourcemap_html_helper.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// Helper for creating HTML visualization of the source map information
 /// generated by a [SourceMapProcessor].
 
 library sourcemap.html.helper;
 
 import 'dart:convert';
 
 import 'package:compiler/src/io/source_file.dart';
 import 'package:compiler/src/io/source_information.dart';
 import 'package:compiler/src/js/js.dart' as js;
 
 import 'colors.dart';
 import 'sourcemap_helper.dart';
 import 'sourcemap_html_templates.dart';
 
 /// Returns the [index]th color for visualization.
-String toColor(int index) {
+HSV toColor(int index) {
   int hueCount = 24;
   double h = 360.0 * (index % hueCount) / hueCount;
   double v = 1.0;
   double s = 0.5;
-  HSV hsv = new HSV(h, s, v);
-  RGB rgb = HSV.toRGB(hsv);
-  return rgb.toHex;
+  return new HSV(h, s, v);
+}
+
+/// Return the CSS color value for the [index]th color.
+String toColorCss(int index) {
+  return toColor(index).toCss;
+}
+
+/// Return the CSS color value for the [index]th span.
+String toPattern(int index) {
+  /// Use gradient on spans to visually identify consecutive spans mapped to the
+  /// same source location.
+  HSV startColor = toColor(index);
+  HSV endColor = new HSV(startColor.h, startColor.s + 0.4, startColor.v - 0.2);
+  return 'linear-gradient(to right, ${startColor.toCss}, ${endColor.toCss})';
 }
 
 /// Return the html for the [index] line number.
 String lineNumber(int index) {
   return '<span class="lineNumber">${index + 1} </span>';
 }
 
 /// Return the html escaped [text].
 String escape(String text) {
   return const HtmlEscape().convert(text);
@@ skipping 85 matching lines @@
     void insertSourceLocations(List<SourceLocation> lastSourceLocations) {
       endCurrentLocation();
 
       String color;
       int index;
       String title;
       if (lastSourceLocations.length == 1) {
         SourceLocation sourceLocation = lastSourceLocations.single;
         if (sourceLocation != null) {
           index = collection.getIndex(sourceLocation);
-          color = "background:#${toColor(index)};";
+          color = "background:${toPattern(index)};";
           title = sourceLocation.shortText;
           currentLocation = sourceLocation;
         }
       } else {
 
         index = collection.getIndex(lastSourceLocations.first);
         StringBuffer sb = new StringBuffer();
         double delta = 100.0 / (lastSourceLocations.length);
         double position = 0.0;
 
         void addColor(String color) {
           sb.write(', ${color} ${position.toInt()}%');
           position += delta;
           sb.write(', ${color} ${position.toInt()}%');
         }
 
         for (SourceLocation sourceLocation in lastSourceLocations) {
           if (sourceLocation == null) continue;
           int colorIndex = collection.getIndex(sourceLocation);
-          addColor('#${toColor(colorIndex)}');
+          addColor('${toColorCss(colorIndex)}');
           currentLocation = sourceLocation;
         }
         color = 'background: linear-gradient(to right${sb}); '
                 'background-size: 10px 10px;';
         title = lastSourceLocations.map((l) => l.shortText).join(',');
       }
       if (index != null) {
         Set<int> indices =
             lastSourceLocations.map((l) => collection.getIndex(l)).toSet();
         String onmouseover = indices.map((i) => '\'$i\'').join(',');
@@ skipping 191 matching lines @@
         int start = sourceLocation.column;
         int end = line.length;
         if (i + 1 < locations.length) {
           end = locations[i + 1].column;
         }
         if (i == 0) {
           codeBuffer.write(lineNumber(lineIndex));
           codeBuffer.write(line.substring(0, start));
         }
         codeBuffer.write(
-            '<a name="${index}" style="background:#${toColor(index)};" '
+            '<a name="${index}" style="background:${toPattern(index)};" '
             'title="[${lineIndex + 1},${start + 1}]" '
             'onmouseover="highlight(\'$index\');" '
             'onmouseout="highlight();">');
         codeBuffer.write(line.substring(start, end));
         codeBuffer.write('</a>');
       }
       lastLineIndex = lineIndex;
     });
 
     flush();
   });
   String display = showAsBlock ? 'block' : 'none';
   return '''
 <div name="$name" class="dart-buffer" style="display:$display;">
 <h3>Dart code for: ${escape(name)}</h3>
 ${dartCodeBuffer}
 </div>''';
 }
 
 /// Computes a HTML visualization of the [codePoints].
 String computeJsTraceHtmlPart(List<CodePoint> codePoints,
                               SourceLocationCollection collection) {
   StringBuffer buffer = new StringBuffer();
   buffer.write('<table style="width:100%;">');
   buffer.write(
       '<tr><th>Node kind</th><th>JS code @ offset</th>'
       '<th>Dart code @ mapped location</th><th>file:position:name</th></tr>');
   codePoints.forEach((CodePoint codePoint) {
     String jsCode = codePoint.jsCode;
-    if (jsCode.length > 40) {
-      jsCode = jsCode.substring(0, 40);
-    }
     if (codePoint.sourceLocation != null) {
       int index = collection.getIndex(codePoint.sourceLocation);
       if (index != null) {
-
-        buffer.write('<tr style="background:#${toColor(index)};" '
+        String style = '';
+        if (!codePoint.isMissing) {
+          style = 'style="background:${toColorCss(index)};" ';
+        }
+        buffer.write('<tr $style'
                      'name="trace$index" '
                      'onmouseover="highlight([${index}]);"'
                      'onmouseout="highlight([]);">');
       } else {
         buffer.write('<tr>');
         print('${codePoint.sourceLocation} not found in ');
         collection.sourceLocationIndexMap.keys
             .where((l) => l.sourceUri == codePoint.sourceLocation.sourceUri)
             .forEach((l) => print(' $l'));
       }
     } else {
       buffer.write('<tr>');
     }
     buffer.write('<td>${codePoint.kind}</td>');
     buffer.write('<td class="code">${jsCode}</td>');
     if (codePoint.sourceLocation == null) {
       //buffer.write('<td></td>');
     } else {
       buffer.write('<td class="code">${codePoint.dartCode}</td>');
       buffer.write('<td>${escape(codePoint.sourceLocation.shortText)}</td>');
     }
     buffer.write('</tr>');
   });
   buffer.write('</table>');
 
   return buffer.toString();
 }