DevTools: use timing information for "disk cached" resources.

Source/devtools/front_end/sdk/NetworkRequest.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 336 matching lines @@
     },
 
     set canceled(x)
     {
         this._canceled = x;
     },
 
     /**
      * @return {boolean}
      */
-    get cached()
+    cached: function()
     {
-        return !!this._cached && !this._transferSize;
+        return (!!this._fromMemoryCache || !!this._fromDiskCache) && !this._transferSize;
     },
 
-    set cached(x)
+    setFromMemoryCache: function()
     {
-        this._cached = x;
-        if (x)
-            delete this._timing;
+        this._fromMemoryCache = true;
+        delete this._timing;
+    },
+
+    setFromDiskCache: function()
+    {
+        this._fromDiskCache = true;
     },
 
     /**
      * @return {boolean}
      */
     get fetchedViaServiceWorker()
     {
         return this._fetchedViaServiceWorker;
     },
 
     set fetchedViaServiceWorker(x)
     {
         this._fetchedViaServiceWorker = x;
     },
 
     /**
      * @return {!NetworkAgent.ResourceTiming|undefined}
      */
     get timing()
     {
         return this._timing;
     },
 
     set timing(x)
     {
-        if (x && !this._cached) {
+        if (x && !this._fromMemoryCache) {
             // Take startTime and responseReceivedTime from timing data for better accuracy.
             // Timing's requestTime is a baseline in seconds, rest of the numbers there are ticks in millis.
             this._startTime = x.requestTime;
             this._responseReceivedTime = x.requestTime + x.receiveHeadersEnd / 1000.0;
 
             this._timing = x;
             this.dispatchEventToListeners(WebInspector.NetworkRequest.Events.TimingChanged, this);
         }
     },
 
@@ skipping 583 matching lines @@
      * @param {boolean} sent
      */
     addFrame: function(response, time, sent)
     {
         var type = sent ? WebInspector.NetworkRequest.WebSocketFrameType.Send : WebInspector.NetworkRequest.WebSocketFrameType.Receive;
         this._frames.push({ type: type, text: response.payloadData, time: time, opCode: response.opcode, mask: response.mask });
     },
 
     __proto__: WebInspector.SDKObject.prototype
 }