[NoStatePrefetch] Remove obsolete histograms

chrome/browser/prerender/prerender_nostate_prefetch_browsertest.cc

 // Copyright (c) 2012 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.
 
 #include "base/command_line.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_split.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/task_scheduler/post_task.h"
 #include "chrome/browser/history/history_service_factory.h"
@@ skipping 147 matching lines @@
   test_prerender->WaitForLoads(0);
 }
 
 // Check that a prefetch followed by a load produces the approriate
 // histograms. Note that other histogram testing is done in
 // browser/page_load_metrics, in particular, testing the combinations of
 // Warm/Cold and Cacheable/NoCacheable.
 IN_PROC_BROWSER_TEST_F(NoStatePrefetchBrowserTest, PrefetchHistograms) {
   PrefetchFromFile(kPrefetchPage, FINAL_STATUS_NOSTATE_PREFETCH_FINISHED);
   histogram_tester().ExpectTotalCount(
-      "Prerender.websame_NoStatePrefetchTTFCP.Warm", 0);
+      "Prerender.websame_PrefetchTTFCP.Warm.Cacheable.Visible", 0);
 
   test_utils::FirstContentfulPaintManagerWaiter* fcp_waiter =
       test_utils::FirstContentfulPaintManagerWaiter::Create(
           GetPrerenderManager());
   ui_test_utils::NavigateToURL(
       current_browser(), src_server()->GetURL(MakeAbsolute(kPrefetchPage)));
   fcp_waiter->Wait();
 
   histogram_tester().ExpectTotalCount(
       "Prerender.websame_PrefetchTTFCP.Warm.Cacheable.Visible", 1);
@@ skipping 418 matching lines @@
   // The SW intercepts kPrefetchPage and replaces it with a body that contains
   // an <img> tage for kPrefetchPng. This verifies that the SW ran correctly by
   // observing the fetch of the image.
   RequestCounter image_counter;
   CountRequestFor(kPrefetchPng, &image_counter);
   PrefetchFromFile(kPrefetchPage, FINAL_STATUS_NOSTATE_PREFETCH_FINISHED);
   image_counter.WaitForCount(1);
 }
 
 }  // namespace prerender