FontResourceTest: call unregisterURL() respectively

third_party/WebKit/public/platform/WebURLLoaderMockFactory.h

 // Copyright 2016 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.
 
 #ifndef WebURLLoaderMockFactory_h
 #define WebURLLoaderMockFactory_h
 
 #include "public/platform/WebCommon.h"
 #include "public/platform/WebData.h"
 #include "public/platform/WebString.h"
@@ skipping 14 matching lines @@
 
   virtual ~WebURLLoaderMockFactory() {}
 
   // Create a WebURLLoader that takes care of mocked requests.
   // Non-mocked request are forwarded to given loader which should not
   // be nullptr.
   virtual WebURLLoader* createURLLoader(WebURLLoader*) = 0;
 
   // Registers a response and the file to be served when the specified URL
   // is loaded. If no file is specified then the response content will be empty.
+  // unregisterURL() should be called for each test entry before registering
+  // another response for the same URL from another test.
   virtual void registerURL(const WebURL&,
                            const WebURLResponse&,
                            const WebString& filePath) = 0;
 
   // Registers an error to be served when the specified URL is requested.
+  // unregisterURL() should be called for each test entry before registering
+  // another response for the same URL from another test.
   virtual void registerErrorURL(const WebURL&,
                                 const WebURLResponse&,
                                 const WebURLError&) = 0;
 
   // Unregisters URLs so they are no longer mocked.
   virtual void unregisterURL(const WebURL&) = 0;
   virtual void unregisterAllURLs() = 0;
 
   // Causes all pending asynchronous requests to be served. When this method
   // returns all the pending requests have been processed.
   // Note: this may not work as expected if more requests could be made
   // asynchronously from different threads (e.g. when HTML parser thread
   // is being involved).
   // DO NOT USE THIS for Frame loading; always use methods defined in
   // FrameTestHelpers instead.
   virtual void serveAsynchronousRequests() = 0;
 
   // Set a delegate that allows callbacks for all WebURLLoaderClients to be
   // intercepted.
   virtual void setLoaderDelegate(WebURLLoaderTestDelegate*) = 0;
 };
 
 }  // namespace blink
 
 #endif  // WebURLLoaderMockFactory_h