DevTools: report error when DevTools fail to parse SourceMap.

third_party/WebKit/Source/devtools/front_end/sdk/SourceMap.js

 /*
  * Copyright (C) 2012 Google Inc. 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
@@ skipping 104 matching lines @@
         }
 
         if (content.slice(0, 3) === ")]}")
             content = content.substring(content.indexOf('\n'));
         try {
             var payload = /** @type {!SourceMapV3} */ (JSON.parse(content));
             var baseURL = sourceMapURL.startsWith("data:") ? compiledURL : sourceMapURL;
             callback(new WebInspector.SourceMap(baseURL, payload));
         } catch(e) {
             console.error(e.message);
+            WebInspector.console.error("Failed to parse SourceMap: " + sourceMapURL);
             callback(null);
         }
     }
 }
 
 WebInspector.SourceMap.prototype = {
     /**
      * @return {string}
      */
     url: function()
@@ skipping 292 matching lines @@
  * @param {number=} sourceColumnNumber
  */
 WebInspector.SourceMap.Entry = function(lineNumber, columnNumber, sourceURL, sourceLineNumber, sourceColumnNumber)
 {
     this.lineNumber = lineNumber;
     this.columnNumber = columnNumber;
     this.sourceURL = sourceURL;
     this.sourceLineNumber = sourceLineNumber;
     this.sourceColumnNumber = sourceColumnNumber;
 }