Only set precache.last_time when precache ran.

components/precache/content/precache_manager_unittest.cc

 // Copyright 2013 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 "components/precache/content/precache_manager.h"
 
 #include <map>
 #include <set>
 #include <string>
 
@@ skipping 86 matching lines @@
 };
 
 ACTION_P(ReturnHosts, starting_hosts) {
   arg1.Run(starting_hosts);
 }
 
 class TestPrecacheCompletionCallback {
  public:
   TestPrecacheCompletionCallback() : was_on_done_called_(false) {}
 
-  void OnDone() {
-    was_on_done_called_ = true;
-  }
+  void OnDone(bool precaching_started) { was_on_done_called_ = true; }
 
   PrecacheManager::PrecacheCompletionCallback GetCallback() {
     return base::Bind(&TestPrecacheCompletionCallback::OnDone,
                       base::Unretained(this));
   }
 
   bool was_on_done_called() const {
     return was_on_done_called_;
   }
 
@@ skipping 250 matching lines @@
       kCurrentTime, 1000, true);
   expected_histogram_count_map["Precache.Saved"] += 2;
 
   base::MessageLoop::current()->RunUntilIdle();
   EXPECT_EQ(expected_histogram_count_map, GetHistogramCountMap());
 }
 
 }  // namespace
 
 }  // namespace precache