[DevTools] Resources: add "copy image as data url" menu item.

Source/devtools/front_end/ImageView.js

 /*
  * Copyright (C) 2007, 2008 Apple 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 92 matching lines @@
             dt.textContent = WebInspector.UIString("URL");
             infoListElement.appendChild(dt);
             var dd = document.createElement("dd");
             var externalResource = true;
             dd.appendChild(WebInspector.linkifyURLAsNode(this.resource.url, undefined, undefined, externalResource));
             infoListElement.appendChild(dd);
 
             this._container.appendChild(infoListElement);
         }
         imagePreviewElement.addEventListener("load", onImageLoad.bind(this), false);
+        this._imagePreviewElement = imagePreviewElement;
     },
 
     _base64ToSize: function(content)
     {
         if (!content.length)
             return 0;
         var size = (content.length || 0) * 3 / 4;
         if (content.length > 0 && content[content.length - 1] === "=")
             size--;
         if (content.length > 1 && content[content.length - 2] === "=")
             size--;
         return size;
     },
 
     _contextMenu: function(event)
     {
         var contextMenu = new WebInspector.ContextMenu(event);
         contextMenu.appendItem(WebInspector.UIString(WebInspector.useLowerCaseMenuTitles() ? "Copy image URL" : "Copy Image URL"), this._copyImageURL.bind(this));
+        if (this._imagePreviewElement.src)
+            contextMenu.appendItem(WebInspector.UIString(WebInspector.useLowerCaseMenuTitles() ? "Copy image as Data URL" : "Copy Image As Data URL"), this._copyImageAsDataURL.bind(this));
         contextMenu.appendItem(WebInspector.UIString(WebInspector.useLowerCaseMenuTitles() ? "Open image in new tab" : "Open Image in New Tab"), this._openInNewTab.bind(this));
         contextMenu.show();
     },
 
+    _copyImageAsDataURL: function()
+    {
+        InspectorFrontendHost.copyText(this._imagePreviewElement.src);
+    },
+
     _copyImageURL: function()
     {
         InspectorFrontendHost.copyText(this.resource.url);
     },
 
     _openInNewTab: function()
     {
         InspectorFrontendHost.openInNewTab(this.resource.url);
     },
 
     __proto__: WebInspector.ResourceView.prototype
 }