DevTools: introduce WI.SourceMap.Entry structure and cleanup WI.SourceMap API.

Source/devtools/front_end/bindings/SASSSourceMapping.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 537 matching lines @@
         }
     },
 
     /**
      * @override
      * @param {!WebInspector.CSSLocation} rawLocation
      * @return {?WebInspector.UILocation}
      */
     rawLocationToUILocation: function(rawLocation)
     {
-        var entry;
         var sourceMap = this._sourceMapByStyleSheetURL[rawLocation.url];
         if (!sourceMap)
             return null;
-        entry = sourceMap.findEntry(rawLocation.lineNumber, rawLocation.columnNumber);
-        if (!entry || entry.length === 2)
+        var entry = sourceMap.findEntry(rawLocation.lineNumber, rawLocation.columnNumber);
+        if (!entry || !entry.sourceURL)
             return null;
-        var uiSourceCode = this._networkMapping.uiSourceCodeForURL(entry[2], rawLocation.target());
+        var uiSourceCode = this._networkMapping.uiSourceCodeForURL(entry.sourceURL, rawLocation.target());
         if (!uiSourceCode)
             return null;
-        return uiSourceCode.uiLocation(entry[3], entry[4]);
+        return uiSourceCode.uiLocation(entry.sourceLineNumber, entry.sourceColumnNumber);
     },
 
     /**
      * @override
      * @param {!WebInspector.UISourceCode} uiSourceCode
      * @param {number} lineNumber
      * @param {number} columnNumber
      * @return {?WebInspector.CSSLocation}
      */
     uiLocationToRawLocation: function(uiSourceCode, lineNumber, columnNumber)
@@ skipping 68 matching lines @@
         this._cssURLsForSASSURL = {};
         /** @type {!Object.<string, !Array.<function(?WebInspector.SourceMap)>>} */
         this._pendingSourceMapLoadingCallbacks = {};
         /** @type {!Object.<string, !{deadlineMs: number, dataByURL: !Object.<string, !{timer: number, previousPoll: number}>}>} */
         this._pollDataForSASSURL = {};
         /** @type {!Object.<string, !WebInspector.SourceMap>} */
         this._sourceMapByURL = {};
         this._sourceMapByStyleSheetURL = {};
     }
 }