Refactor cache counting into a separate helper class

chrome/browser/browsing_data/cache_counter_browsertest.cc

 // Copyright (c) 2015 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.
 //
 // Note that this file only tests the basic behavior of the cache counter, as in
 // when it counts and when not, when result is nonzero and when not. It does not
 // test whether the result of the counting is correct. This is the
 // responsibility of a lower layer, and is tested in
 // DiskCacheBackendTest.CalculateSizeOfAllEntries in net_unittests.
 
@@ skipping 234 matching lines @@
   Profile* profile = browser()->profile();
   CacheCounter counter(profile);
   counter.Init(
       profile->GetPrefs(),
       base::Bind(&CacheCounterTest::CountingCallback, base::Unretained(this)));
   counter.Restart();
 
   EXPECT_FALSE(counter.Pending());
 }
 
-// Tests that the counting is restarted when the time period changes. Currently,
-// the results should be the same for every period. This is because the counter
-// always counts the size of the entire cache, and it is up to the UI
-// to interpret it as exact value or upper bound.
+// Tests that the counting is restarted when the time period changes.

[msramek, 2016/12/15 15:58:50]

Can you add tests for the new behavior?

At minimum, we should test |is_upper_limit|.

Ideally, the test should also be able to inject a smaller time limit and test
the switch from exact computation to the estimate.

[dullweber, 2016/12/16 16:41:10]

I added a test that sets timeout to 0 and checks if is_upper_limit is true. I
also tested that is_upper_limit returns false for the other cases.

 IN_PROC_BROWSER_TEST_F(CacheCounterTest, PeriodChanged) {
   CreateCacheEntry();
 
   Profile* profile = browser()->profile();
   CacheCounter counter(profile);
   counter.Init(
       profile->GetPrefs(),
       base::Bind(&CacheCounterTest::CountingCallback, base::Unretained(this)));
 
   SetDeletionPeriodPref(browsing_data::LAST_HOUR);
@@ skipping 11 matching lines @@
   SetDeletionPeriodPref(browsing_data::FOUR_WEEKS);
   WaitForIOThread();
   EXPECT_EQ(result, GetResult());
 
   SetDeletionPeriodPref(browsing_data::ALL_TIME);
   WaitForIOThread();
   EXPECT_EQ(result, GetResult());
 }
 
 }  // namespace