Make SDCH dictionaries persistent across browser restart.

net/sdch/sdch_owner_unittest.cc

 // Copyright 2014 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/memory/memory_pressure_listener.h"
+#include "base/prefs/testing_pref_store.h"
 #include "base/run_loop.h"
 #include "base/strings/stringprintf.h"
 #include "base/test/simple_test_clock.h"
+#include "base/values.h"
 #include "net/base/net_log.h"
 #include "net/base/sdch_manager.h"
 #include "net/sdch/sdch_owner.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_error_job.h"
 #include "net/url_request/url_request_job.h"
 #include "net/url_request/url_request_job_factory.h"
+#include "net/url_request/url_request_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+namespace {
+
+bool GetDictionaryForURL(TestingPrefStore* store,
+                         const GURL& url,
+                         std::string* hash,
+                         base::DictionaryValue** dict) {
+  base::Value* sdch_val = nullptr;
+  base::DictionaryValue* sdch_dict = nullptr;
+  if (!store->GetMutableValue("SDCH", &sdch_val))
+    return false;
+  if (!sdch_val->GetAsDictionary(&sdch_dict))
+    return false;
+
+  base::DictionaryValue* dicts_dict = nullptr;
+  if (!sdch_dict->GetDictionary("dictionaries", &dicts_dict))
+    return false;
+
+  base::DictionaryValue::Iterator it(*dicts_dict);
+  while (!it.IsAtEnd()) {
+    const base::DictionaryValue* d = nullptr;
+    if (!it.value().GetAsDictionary(&d))
+      continue;
+    std::string dict_url;
+    if (d->GetString("url", &dict_url) && dict_url == url.spec()) {
+      if (hash)
+        *hash = it.key();
+      if (dict)
+        dicts_dict->GetDictionary(it.key(), dict);
+      return true;
+    }
+    it.Advance();
+  }
+
+  return false;
+}
+
+}  // namespace
+
 namespace net {
 
 static const char generic_url[] = "http://www.example.com";
 static const char generic_domain[] = "www.example.com";
 
 static std::string NewSdchDictionary(size_t dictionary_size) {
   std::string dictionary;
   dictionary.append("Domain: ");
   dictionary.append(generic_domain);
   dictionary.append("\n");
@@ skipping 84 matching lines @@
 
   bool IsHandledURL(const GURL& url) const override {
     return url.SchemeIs("http");
   }
 
   bool IsSafeRedirectTarget(const GURL& location) const override {
     return false;
   }
 };
 
+class MockSdchDictionaryFetcher : public SdchDictionaryFetcher {
+ public:
+  MockSdchDictionaryFetcher() : SdchDictionaryFetcher(&test_context_) {}
+  ~MockSdchDictionaryFetcher() {}
+
+  struct PendingRequest {
+    PendingRequest(const GURL& url,
+                   const OnDictionaryFetchedCallback& callback)
+        : url_(url), callback_(callback) {}
+    GURL url_;
+    OnDictionaryFetchedCallback callback_;
+  };
+
+  virtual bool Schedule(const GURL& dictionary_url,
+                        const OnDictionaryFetchedCallback& callback) {
+    if (!HasPendingRequest(dictionary_url)) {
+      requests_.push_back(PendingRequest(dictionary_url, callback));
+      return true;
+    }
+    return false;
+  }
+
+  virtual bool ScheduleReload(const GURL& dictionary_url,
+                              const OnDictionaryFetchedCallback& callback) {
+    if (!HasPendingRequest(dictionary_url)) {
+      requests_.push_back(PendingRequest(dictionary_url, callback));
+      return true;
+    }
+    return false;
+  }
+
+  virtual void Cancel() {
+    requests_.clear();
+  }
+
+  bool HasPendingRequest(const GURL& dictionary_url) {
+    for (std::vector<PendingRequest>::iterator it = requests_.begin();
+         it != requests_.end(); ++it) {
+      if (it->url_ == dictionary_url)
+        return true;
+    }
+    return false;
+  }
+
+  bool CompletePendingRequest(const GURL& dictionary_url,
+                              const std::string& dictionary_text,
+                              const BoundNetLog& net_log) {
+    for (std::vector<PendingRequest>::iterator it = requests_.begin();
+         it != requests_.end(); ++it) {
+      if (it->url_ == dictionary_url) {
+        it->callback_.Run(dictionary_text, dictionary_url, net_log);
+        requests_.erase(it);
+        return true;
+      }
+    }
+    return false;
+  }
+
+ private:
+  TestURLRequestContext test_context_;
+  std::vector<PendingRequest> requests_;
+  DISALLOW_COPY_AND_ASSIGN(MockSdchDictionaryFetcher);
+};
+
+// File testing infrastructure summary:
+// * NewSdchDictionary(): Creates a dictionary of a specific size.
+// * URLRequestErrorCountingJob: A URLRequestJob that returns an error
+//   and counts the number of outstanding (started but not finished)
+//   jobs, and calls a global callback when that number transitions to zero.
+// * MockURLRequestJobFactory: Factory to create the above jobs.  Tracks
+//   the number of jobs created.
+// * SdchOwnerTest: Interfaces
+//      * Access manager, owner, and net log
+//      * Return the number of jobs created in a time interval
+//      * Return dictionary present in the manager
+//      * Notify SdchOwner of an incoming dictionary (& wait until jobs clear)
+//      * Attempt to add a dictionary and test for success.
+// Test patterns:
+//      * Let the owner know about a Get-Dictionary header and test for
+//        appropriate jobs being created.
+//      * Let the owner know that a dictionary was successfully fetched
+//        and test for appropriate outcome.
+//      * Either of the above, having previously added dictionaries to create
+//        a particular initial state.
 class SdchOwnerTest : public testing::Test {
  public:
   static const size_t kMaxSizeForTesting = 1000 * 50;
   static const size_t kMinFetchSpaceForTesting = 500;
 
   SdchOwnerTest()
       : last_jobs_created_(error_jobs_created),
         dictionary_creation_index_(0),
+        pref_store_(new TestingPrefStore),
         sdch_owner_(&sdch_manager_, &url_request_context_) {
     // Any jobs created on this context will immediately error,
     // which leaves the test in control of signals to SdchOwner.
     url_request_context_.set_job_factory(&job_factory_);
 
     // Reduce sizes to reduce time for string operations.
     sdch_owner_.SetMaxTotalDictionarySize(kMaxSizeForTesting);
     sdch_owner_.SetMinSpaceForDictionaryFetch(kMinFetchSpaceForTesting);
   }
 
   SdchManager& sdch_manager() { return sdch_manager_; }
   SdchOwner& sdch_owner() { return sdch_owner_; }
   BoundNetLog& bound_net_log() { return net_log_; }
+  TestingPrefStore& pref_store() { return *(pref_store_.get()); }
 
   int JobsRecentlyCreated() {
     int result = error_jobs_created - last_jobs_created_;
     last_jobs_created_ = error_jobs_created;
     return result;
   }
 
   bool DictionaryPresentInManager(const std::string& server_hash) {
     // Presumes all tests use generic url.
     SdchProblemCode tmp;
     scoped_ptr<SdchManager::DictionarySet> set(
         sdch_manager_.GetDictionarySetByHash(GURL(generic_url), server_hash,
                                              &tmp));
     return !!set.get();
   }
 
-  void SignalGetDictionaryAndClearJobs(GURL request_url, GURL dictionary_url) {
-    sdch_owner().OnGetDictionary(&sdch_manager_, request_url, dictionary_url);
+  void WaitForNoJobs() {
     if (outstanding_url_request_error_counting_jobs == 0)
       return;
+
     base::RunLoop run_loop;
     base::Closure quit_closure(run_loop.QuitClosure());
     empty_url_request_jobs_callback = &quit_closure;
     run_loop.Run();
     empty_url_request_jobs_callback = NULL;
   }
 
+  void SignalGetDictionaryAndClearJobs(GURL request_url, GURL dictionary_url) {
+    sdch_owner().OnGetDictionary(&sdch_manager_, request_url, dictionary_url);
+    WaitForNoJobs();
+  }
+
   // Create a unique (by hash) dictionary of the given size,
   // associate it with a unique URL, add it to the manager through
   // SdchOwner::OnDictionaryFetched(), and return whether that
   // addition was successful or not.
-  bool CreateAndAddDictionary(size_t size, std::string* server_hash_p) {
+  bool CreateAndAddDictionary(size_t size,
+                              std::string* server_hash_p,
+                              base::Time last_used_time) {
     GURL dictionary_url(
         base::StringPrintf("%s/d%d", generic_url, dictionary_creation_index_));
     std::string dictionary_text(NewSdchDictionary(size - 4));
     dictionary_text += base::StringPrintf("%04d", dictionary_creation_index_);
     ++dictionary_creation_index_;
     std::string client_hash;
     std::string server_hash;
     SdchManager::GenerateHash(dictionary_text, &client_hash, &server_hash);
 
     if (DictionaryPresentInManager(server_hash))
       return false;
-    sdch_owner().OnDictionaryFetched(dictionary_text, dictionary_url, net_log_);
+    sdch_owner().OnDictionaryFetched(last_used_time, 0, dictionary_text,
+                                     dictionary_url, net_log_);
     if (server_hash_p)
       *server_hash_p = server_hash;
     return DictionaryPresentInManager(server_hash);
   }
 
  private:
   int last_jobs_created_;
   BoundNetLog net_log_;
   int dictionary_creation_index_;
 
   // The dependencies of these objects (sdch_owner_ -> {sdch_manager_,
   // url_request_context_}, url_request_context_->job_factory_) require
   // this order for correct destruction semantics.
   MockURLRequestJobFactory job_factory_;
   URLRequestContext url_request_context_;
   SdchManager sdch_manager_;
+  scoped_refptr<TestingPrefStore> pref_store_;
   SdchOwner sdch_owner_;
 
   DISALLOW_COPY_AND_ASSIGN(SdchOwnerTest);
 };
 
 // Does OnGetDictionary result in a fetch when there's enough space, and not
 // when there's not?
 TEST_F(SdchOwnerTest, OnGetDictionary_Fetching) {
   GURL request_url(std::string(generic_url) + "/r1");
 
   // Fetch generated when empty.
   GURL dict_url1(std::string(generic_url) + "/d1");
   EXPECT_EQ(0, JobsRecentlyCreated());
   SignalGetDictionaryAndClearJobs(request_url, dict_url1);
   EXPECT_EQ(1, JobsRecentlyCreated());
 
   // Fetch generated when half full.
   GURL dict_url2(std::string(generic_url) + "/d2");
   std::string dictionary1(NewSdchDictionary(kMaxSizeForTesting / 2));
-  sdch_owner().OnDictionaryFetched(dictionary1, dict_url1, bound_net_log());
+  sdch_owner().OnDictionaryFetched(base::Time::Now(), 1, dictionary1, dict_url1,
+                                   bound_net_log());
   EXPECT_EQ(0, JobsRecentlyCreated());
   SignalGetDictionaryAndClearJobs(request_url, dict_url2);
   EXPECT_EQ(1, JobsRecentlyCreated());
 
   // Fetch not generated when close to completely full.
   GURL dict_url3(std::string(generic_url) + "/d3");
   std::string dictionary2(NewSdchDictionary(
       (kMaxSizeForTesting / 2 - kMinFetchSpaceForTesting / 2)));
-  sdch_owner().OnDictionaryFetched(dictionary2, dict_url2, bound_net_log());
+  sdch_owner().OnDictionaryFetched(base::Time::Now(), 1, dictionary2, dict_url2,
+                                   bound_net_log());
   EXPECT_EQ(0, JobsRecentlyCreated());
   SignalGetDictionaryAndClearJobs(request_url, dict_url3);
   EXPECT_EQ(0, JobsRecentlyCreated());
 }
 
 // Make sure attempts to add dictionaries do what they should.
 TEST_F(SdchOwnerTest, OnDictionaryFetched_Fetching) {
   GURL request_url(std::string(generic_url) + "/r1");
   std::string client_hash;
   std::string server_hash;
 
+  // In the past, but still fresh for an unused dictionary.
+  base::Time dictionary_last_used_time(base::Time::Now() -
+                                       base::TimeDelta::FromMinutes(30));
+
   // Add successful when empty.
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 2, nullptr));
+  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 2, nullptr,
+                                     dictionary_last_used_time));
   EXPECT_EQ(0, JobsRecentlyCreated());
 
   // Add successful when half full.
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 2, nullptr));
+  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 2, nullptr,
+                                     dictionary_last_used_time));
   EXPECT_EQ(0, JobsRecentlyCreated());
 
   // Add unsuccessful when full.
-  EXPECT_FALSE(CreateAndAddDictionary(kMaxSizeForTesting / 2, nullptr));
+  EXPECT_FALSE(CreateAndAddDictionary(kMaxSizeForTesting / 2, nullptr,
+                                      dictionary_last_used_time));
   EXPECT_EQ(0, JobsRecentlyCreated());
 }
 
 // Confirm auto-eviction happens if space is needed.
 TEST_F(SdchOwnerTest, ConfirmAutoEviction) {
   std::string server_hash_d1;
   std::string server_hash_d2;
   std::string server_hash_d3;
 
   // Add two dictionaries, one recent, one more than a day in the past.
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d1));
+  base::Time fresh(base::Time::Now() - base::TimeDelta::FromHours(23));
+  base::Time stale(base::Time::Now() - base::TimeDelta::FromHours(25));
 
-  scoped_ptr<base::SimpleTestClock> clock(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now() - base::TimeDelta::FromDays(2));
-  sdch_owner().SetClockForTesting(clock.Pass());
-
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d2));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d1, fresh));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d2, stale));
 
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d2));
 
-  // The addition of a new dictionary should succeed, evicting the old one.
-  clock.reset(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now());
-  sdch_owner().SetClockForTesting(clock.Pass());
-
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d3));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d3, fresh));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d2));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d3));
 }
 
 // Confirm auto-eviction happens if space is needed, with a more complicated
 // situation
 TEST_F(SdchOwnerTest, ConfirmAutoEviction_2) {
   std::string server_hash_d1;
   std::string server_hash_d2;
   std::string server_hash_d3;
 
   // Add dictionaries, one recent, two more than a day in the past that
   // between them add up to the space needed.
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d1));
+  base::Time fresh(base::Time::Now() - base::TimeDelta::FromHours(23));
+  base::Time stale(base::Time::Now() - base::TimeDelta::FromHours(25));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d1, fresh));
 
-  scoped_ptr<base::SimpleTestClock> clock(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now() - base::TimeDelta::FromDays(2));
-  sdch_owner().SetClockForTesting(clock.Pass());
-
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d2));
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d3));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d2, stale));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d3, stale));
 
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d2));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d3));
 
-  // The addition of a new dictionary should succeed, evicting the old one.
-  clock.reset(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now());
-  sdch_owner().SetClockForTesting(clock.Pass());
-
   std::string server_hash_d4;
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d4));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d4, fresh));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d2));
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d3));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d4));
 }
 
 // Confirm if only one dictionary needs to be evicted it's the oldest.
 TEST_F(SdchOwnerTest, ConfirmAutoEviction_Oldest) {
   std::string server_hash_d1;
   std::string server_hash_d2;
   std::string server_hash_d3;
 
   // Add dictionaries, one recent, one two days in the past, and one
   // four days in the past.
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d1));
+  base::Time fresh(base::Time::Now() - base::TimeDelta::FromHours(23));
+  base::Time stale_newer(base::Time::Now() - base::TimeDelta::FromHours(47));
+  base::Time stale_older(base::Time::Now() - base::TimeDelta::FromHours(71));
 
-  scoped_ptr<base::SimpleTestClock> clock(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now() - base::TimeDelta::FromDays(2));
-  sdch_owner().SetClockForTesting(clock.Pass());
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d2));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d1, fresh));
 
-  clock.reset(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now() - base::TimeDelta::FromDays(4));
-  sdch_owner().SetClockForTesting(clock.Pass());
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d3));
+  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d2,
+                                     stale_newer));
+
+  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d3,
+                                     stale_older));
 
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d2));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d3));
 
   // The addition of a new dictionary should succeed, evicting only the
   // oldest one.
-  clock.reset(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now());
-  sdch_owner().SetClockForTesting(clock.Pass());
 
   std::string server_hash_d4;
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d4));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d4, fresh));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d2));
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d3));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d4));
 }
 
 // Confirm using a dictionary changes eviction behavior properly.
 TEST_F(SdchOwnerTest, UseChangesEviction) {
   std::string server_hash_d1;
   std::string server_hash_d2;
   std::string server_hash_d3;
 
   // Add dictionaries, one recent, one two days in the past, and one
   // four days in the past.
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d1));
+  base::Time fresh(base::Time::Now() - base::TimeDelta::FromHours(23));
+  base::Time stale_newer(base::Time::Now() - base::TimeDelta::FromHours(47));
+  base::Time stale_older(base::Time::Now() - base::TimeDelta::FromHours(71));
 
-  scoped_ptr<base::SimpleTestClock> clock(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now() - base::TimeDelta::FromDays(2));
-  sdch_owner().SetClockForTesting(clock.Pass());
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d2));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d1, fresh));
 
-  clock.reset(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now() - base::TimeDelta::FromDays(4));
-  sdch_owner().SetClockForTesting(clock.Pass());
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d3));
+  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d2,
+                                     stale_newer));
+
+  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d3,
+                                     stale_older));
 
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d2));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d3));
 
-  clock.reset(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now());
-  sdch_owner().SetClockForTesting(clock.Pass());
-
   // Use the oldest dictionary.
   sdch_owner().OnDictionaryUsed(&sdch_manager(), server_hash_d3);
 
   // The addition of a new dictionary should succeed, evicting only the
   // newer stale one.
   std::string server_hash_d4;
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d4));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d4, fresh));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d2));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d3));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d4));
 }
 
 // Confirm using a dictionary can prevent the addition of a new dictionary.
 TEST_F(SdchOwnerTest, UsePreventsAddition) {
   std::string server_hash_d1;
   std::string server_hash_d2;
   std::string server_hash_d3;
 
   // Add dictionaries, one recent, one two days in the past, and one
   // four days in the past.
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d1));
+  base::Time fresh(base::Time::Now() - base::TimeDelta::FromMinutes(30));
+  base::Time stale_newer(base::Time::Now() - base::TimeDelta::FromHours(47));
+  base::Time stale_older(base::Time::Now() - base::TimeDelta::FromHours(71));
 
-  scoped_ptr<base::SimpleTestClock> clock(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now() - base::TimeDelta::FromDays(2));
-  sdch_owner().SetClockForTesting(clock.Pass());
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d2));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d1, fresh));
 
-  clock.reset(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now() - base::TimeDelta::FromDays(4));
-  sdch_owner().SetClockForTesting(clock.Pass());
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d3));
+  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d2,
+                                     stale_newer));
+
+  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting / 4, &server_hash_d3,
+                                     stale_older));
 
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d2));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d3));
 
-  clock.reset(new base::SimpleTestClock);
-  clock->SetNow(base::Time::Now());
-  sdch_owner().SetClockForTesting(clock.Pass());
-
   // Use the older dictionaries.
   sdch_owner().OnDictionaryUsed(&sdch_manager(), server_hash_d2);
   sdch_owner().OnDictionaryUsed(&sdch_manager(), server_hash_d3);
 
   // The addition of a new dictionary should fail, not evicting anything.
   std::string server_hash_d4;
-  EXPECT_FALSE(CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d4));
+  EXPECT_FALSE(
+      CreateAndAddDictionary(kMaxSizeForTesting / 2, &server_hash_d4, fresh));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d2));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d3));
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d4));
 }
 
 // Confirm clear gets all the space back.
 TEST_F(SdchOwnerTest, ClearReturnsSpace) {
   std::string server_hash_d1;
   std::string server_hash_d2;
 
   // Take up all the space.
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting, &server_hash_d1));
-
+  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting, &server_hash_d1,
+                                     base::Time::Now()));
   // Addition should fail.
-  EXPECT_FALSE(CreateAndAddDictionary(kMaxSizeForTesting, &server_hash_d2));
-
+  EXPECT_FALSE(CreateAndAddDictionary(kMaxSizeForTesting, &server_hash_d2,
+                                      base::Time::Now()));
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d2));
-
   sdch_manager().ClearData();
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d2));
 
   // Addition should now succeed.
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting, nullptr));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting, nullptr, base::Time::Now()));
 }
 
 // Confirm memory pressure gets all the space back.
 TEST_F(SdchOwnerTest, MemoryPressureReturnsSpace) {
   std::string server_hash_d1;
   std::string server_hash_d2;
 
   // Take up all the space.
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting, &server_hash_d1));
+  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting, &server_hash_d1,
+                                     base::Time::Now()));
 
   // Addition should fail.
-  EXPECT_FALSE(CreateAndAddDictionary(kMaxSizeForTesting, &server_hash_d2));
+  EXPECT_FALSE(CreateAndAddDictionary(kMaxSizeForTesting, &server_hash_d2,
+                                      base::Time::Now()));
 
   EXPECT_TRUE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d2));
 
   base::MemoryPressureListener::NotifyMemoryPressure(
       base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE);
   // The notification may have (implementation note: does :-}) use a PostTask,
   // so we drain the local message queue.  This should be safe (i.e. not have
   // an inifinite number of messages) in a unit test.
   base::RunLoop().RunUntilIdle();
 
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d1));
   EXPECT_FALSE(DictionaryPresentInManager(server_hash_d2));
 
   // Addition should now succeed.
-  EXPECT_TRUE(CreateAndAddDictionary(kMaxSizeForTesting, nullptr));
+  EXPECT_TRUE(
+      CreateAndAddDictionary(kMaxSizeForTesting, nullptr, base::Time::Now()));
+}
+
+class SdchOwnerPersistenceTest : public ::testing::Test {
+ public:
+  SdchOwnerPersistenceTest() : pref_store_(new TestingPrefStore()) {
+    pref_store_->SetInitializationCompleted();
+  }
+  virtual ~SdchOwnerPersistenceTest() {}
+
+  void ClearOwner() {
+    owner_.reset(NULL);
+  }
+
+  void ResetOwner(bool delay) {
+    // This has to be done first, since SdchOwner may be observing SdchManager,
+    // and SdchManager can't be destroyed with a live observer.
+    owner_.reset(NULL);
+    manager_.reset(new SdchManager());
+    fetcher_ = new MockSdchDictionaryFetcher();
+    owner_.reset(new SdchOwner(manager_.get(),
+                               &url_request_context_));
+    owner_->SetMaxTotalDictionarySize(SdchOwnerTest::kMaxSizeForTesting);
+    owner_->SetMinSpaceForDictionaryFetch(
+        SdchOwnerTest::kMinFetchSpaceForTesting);
+    owner_->SetFetcherForTesting(make_scoped_ptr(fetcher_));
+    if (!delay)
+      owner_->EnablePersistentStorage(pref_store_.get());
+  }
+
+  void InsertDictionaryForURL(const GURL& url, const std::string& nonce) {
+    owner_->OnDictionaryFetched(base::Time::Now(), 1,
+                                CreateDictionary(url, nonce),
+                                url, net_log_);
+  }
+
+  bool CompleteLoadFromURL(const GURL& url, const std::string& nonce) {
+    return fetcher_->CompletePendingRequest(url, CreateDictionary(url, nonce),
+                                            net_log_);
+  }
+
+  std::string CreateDictionary(const GURL& url, const std::string& nonce) {
+    std::string dict;
+    dict.append("Domain: ");
+    dict.append(url.host());
+    dict.append("\n\n");
+    dict.append(url.spec());
+    dict.append(nonce);
+    return dict;
+  }
+
+ protected:
+  BoundNetLog net_log_;
+  scoped_refptr<TestingPrefStore> pref_store_;
+  scoped_ptr<SdchManager> manager_;
+  MockSdchDictionaryFetcher* fetcher_;
+  scoped_ptr<SdchOwner> owner_;
+  TestURLRequestContext url_request_context_;
+};
+
+// Test an empty persistence store.
+TEST_F(SdchOwnerPersistenceTest, Empty) {
+  ResetOwner(false);
+  EXPECT_EQ(0, owner_->GetDictionaryCountForTesting());
+}
+
+// Test a persistence store with an empty dictionary.
+TEST_F(SdchOwnerPersistenceTest, Persistent_EmptyDict) {
+  pref_store_->SetValue("SDCH", new base::DictionaryValue());
+  ResetOwner(false);
+  EXPECT_EQ(0, owner_->GetDictionaryCountForTesting());
+}
+
+// Test a persistence store with a bad version number.
+TEST_F(SdchOwnerPersistenceTest, Persistent_BadVersion) {
+  base::DictionaryValue* sdch_dict = new base::DictionaryValue();
+  sdch_dict->SetInteger("version", 2);
+  pref_store_->SetValue("SDCH", sdch_dict);
+
+  ResetOwner(false);
+  EXPECT_EQ(0, owner_->GetDictionaryCountForTesting());
+}
+
+// Test a persistence store with an empty dictionaries map.
+TEST_F(SdchOwnerPersistenceTest, Persistent_EmptyDictList) {
+  base::DictionaryValue* sdch_dict = new base::DictionaryValue();
+  scoped_ptr<base::DictionaryValue> dicts(new base::DictionaryValue());
+  sdch_dict->SetInteger("version", 1);
+  sdch_dict->Set("dictionaries", dicts.Pass());
+  pref_store_->SetValue("SDCH", sdch_dict);
+
+  ResetOwner(false);
+  EXPECT_EQ(0, owner_->GetDictionaryCountForTesting());
+}
+
+TEST_F(SdchOwnerPersistenceTest, OneDict) {
+  const GURL url("http://www.example.com/dict");
+  ResetOwner(false);
+  EXPECT_EQ(0, owner_->GetDictionaryCountForTesting());
+  InsertDictionaryForURL(url, "0");
+  EXPECT_EQ(1, owner_->GetDictionaryCountForTesting());
+
+  ResetOwner(false);
+  EXPECT_EQ(0, owner_->GetDictionaryCountForTesting());
+  EXPECT_TRUE(CompleteLoadFromURL(url, "0"));
+  EXPECT_EQ(1, owner_->GetDictionaryCountForTesting());
+}
+
+TEST_F(SdchOwnerPersistenceTest, TwoDicts) {
+  const GURL url0("http://www.example.com/dict0");
+  const GURL url1("http://www.example.com/dict1");
+  ResetOwner(false);
+  InsertDictionaryForURL(url0, "0");
+  InsertDictionaryForURL(url1, "1");
+
+  ResetOwner(false);
+  EXPECT_TRUE(CompleteLoadFromURL(url0, "0"));
+  EXPECT_TRUE(CompleteLoadFromURL(url1, "1"));
+  EXPECT_EQ(2, owner_->GetDictionaryCountForTesting());
+  EXPECT_TRUE(owner_->HasDictionaryFromURLForTesting(url0));
+  EXPECT_TRUE(owner_->HasDictionaryFromURLForTesting(url1));
+}
+
+TEST_F(SdchOwnerPersistenceTest, OneGoodDictOneBadDict) {
+  const GURL url0("http://www.example.com/dict0");
+  const GURL url1("http://www.example.com/dict1");
+  ResetOwner(false);
+  InsertDictionaryForURL(url0, "0");
+  InsertDictionaryForURL(url1, "1");
+
+  // Mutate the pref store a bit now. Clear the owner first, to ensure that the
+  // SdchOwner doesn't observe these changes and object. The manual dictionary
+  // manipulation is a bit icky.
+  ClearOwner();
+  base::DictionaryValue* dict = nullptr;
+  ASSERT_TRUE(GetDictionaryForURL(pref_store_.get(), url1, nullptr, &dict));
+  dict->Remove("use_count", nullptr);
+
+  ResetOwner(false);
+  EXPECT_TRUE(CompleteLoadFromURL(url0, "0"));
+  EXPECT_FALSE(CompleteLoadFromURL(url1, "1"));
+  EXPECT_EQ(1, owner_->GetDictionaryCountForTesting());
+  EXPECT_TRUE(owner_->HasDictionaryFromURLForTesting(url0));
+  EXPECT_FALSE(owner_->HasDictionaryFromURLForTesting(url1));
+}
+
+TEST_F(SdchOwnerPersistenceTest, UsingDictionaryUpdatesUseCount) {
+  const GURL url("http://www.example.com/dict");
+  ResetOwner(false);
+  InsertDictionaryForURL(url, "0");
+
+  std::string hash;
+  int old_count;
+  {
+    ClearOwner();
+    base::DictionaryValue* dict = nullptr;
+    ASSERT_TRUE(GetDictionaryForURL(pref_store_.get(), url, &hash, &dict));
+    ASSERT_TRUE(dict->GetInteger("use_count", &old_count));
+  }
+
+  ResetOwner(false);
+  ASSERT_TRUE(CompleteLoadFromURL(url, "0"));
+  owner_->OnDictionaryUsed(manager_.get(), hash);
+
+  int new_count;
+  {
+    ClearOwner();
+    base::DictionaryValue* dict = nullptr;
+    ASSERT_TRUE(GetDictionaryForURL(pref_store_.get(), url, nullptr, &dict));
+    ASSERT_TRUE(dict->GetInteger("use_count", &new_count));
+  }
+
+  EXPECT_EQ(old_count + 1, new_count);
+}
+
+TEST_F(SdchOwnerPersistenceTest, LoadingDictionaryMerges) {
+  const GURL url0("http://www.example.com/dict0");
+  const GURL url1("http://www.example.com/dict1");
+
+  ResetOwner(false);
+  InsertDictionaryForURL(url1, "1");
+
+  ResetOwner(true);
+  InsertDictionaryForURL(url0, "0");
+  EXPECT_EQ(1, owner_->GetDictionaryCountForTesting());
+  owner_->EnablePersistentStorage(pref_store_.get());
+  ASSERT_TRUE(CompleteLoadFromURL(url1, "1"));
+  EXPECT_EQ(2, owner_->GetDictionaryCountForTesting());
 }
 
 }  // namespace net