Adds UMA for PrerenderingOffliner request processing result status.

chrome/browser/android/offline_pages/prerendering_loader.cc

 // 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.
 
 #include "chrome/browser/android/offline_pages/prerendering_loader.h"
 
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 146 matching lines @@
   if (IsIdle())
     return;
 
   if (adapter_->IsActive()) {
     DVLOG(1) << "Load failed: " << adapter_->GetFinalStatus();
     adapter_->DestroyActive();
   }
   // Request status depends on whether we are still loading (failed) or
   // did load and then loading was stopped (cancel - from prerender stack).
   Offliner::RequestStatus request_status =
-      IsLoaded() ? Offliner::RequestStatus::CANCELED
-                 : Offliner::RequestStatus::FAILED;
+      IsLoaded() ? Offliner::RequestStatus::LOAD_CANCELED
+                 : Offliner::RequestStatus::LOAD_FAILED;
   // TODO(dougarnett): For failure, determine from final status if retry-able
   // and report different failure statuses if retry-able or not.
   snapshot_controller_.reset(nullptr);
   session_contents_.reset(nullptr);
   state_ = State::IDLE;
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE, base::Bind(callback_, request_status, nullptr));
 }
 
 void PrerenderingLoader::CancelPrerender() {
   if (adapter_->IsActive()) {
     adapter_->DestroyActive();
   }
   snapshot_controller_.reset(nullptr);
   session_contents_.reset(nullptr);
   if (!IsLoaded() && !IsIdle()) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE,
-        base::Bind(callback_, Offliner::RequestStatus::CANCELED, nullptr));
+        base::Bind(callback_, Offliner::RequestStatus::LOAD_CANCELED, nullptr));
   }
   state_ = State::IDLE;
 }
 
 }  // namespace offline_pages