DevTools: add support for polling for coverage data in CSS agent

third_party/WebKit/Source/devtools/front_end/coverage/CoverageModel.js

 // Copyright (c) 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /** @typedef {{startOffset: number, endOffset: number, count: number}} */
 Coverage.RangeUseCount;
 
 /** @typedef {{end: number, count: (number|undefined)}} */
 Coverage.CoverageSegment;
 
@@ skipping 54 matching lines @@
   _processJSCoverage(scriptsCoverage) {
     for (var entry of scriptsCoverage) {
       var script = this._debuggerModel.scriptForId(entry.scriptId);
       if (!script)
         continue;
       var ranges = [];
       for (var func of entry.functions) {
         for (var range of func.ranges)
           ranges.push(range);
       }
-      ranges.sort((a, b) => a.startOffset - b.startOffset);
       this._addCoverage(script, script.contentLength, script.lineOffset, script.columnOffset, ranges);
     }
   }
 
   /**
    * @param {!Array<!Coverage.RangeUseCount>} ranges
    * @return {!Array<!Coverage.CoverageSegment>}
    */
   static _convertToDisjointSegments(ranges) {
+    ranges.sort((a, b) => a.startOffset - b.startOffset);
+
     var result = [];
-
     var stack = [];
     for (var entry of ranges) {
       var top = stack.peekLast();
       while (top && top.endOffset <= entry.startOffset) {
         append(top.endOffset, top.count);
         stack.pop();
         top = stack.peekLast();
       }
       append(entry.startOffset, top ? top.count : undefined);
       stack.push(entry);
@@ skipping 269 matching lines @@
     this._usedSize = 0;
 
     var last = 0;
     for (var segment of this._segments) {
       if (segment.count)
         this._usedSize += segment.end - last;
       last = segment.end;
     }
   }
 };