Refactor net::BackoffEntry to not require subclassing

Before this patch, net::BackoffEntry had a virtual ImplGetTimeNow method
that tests etc would override to change what time is considered "now".

As suggested by rsleevi in https://codereview.chromium.org/1023473003,
this patch removes that method, and instead makes net::BackoffEntry
accept a base::TickClock in the constructor, to allow overriding the
time without subclassing.

(this will allow future changes to net::BackoffEntry without the
fragile base class problem)

Accordingly, I've removed all subclasses of BackoffEntry, and made them
pass TickClocks instead; in most cases this has been a nice
simplification.

BUG=465399
TBR=stevenjb@chromium.org

Review URL: https://codereview.chromium.org/1076853003

Cr-Commit-Position: refs/heads/master@{#325865}

4 files changed, 14 insertions, 40 deletions

diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.cc b/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.cc
index f8e3d9e..af4c571 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.cc
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.cc
@@ -156,7 +156,7 @@ void DataReductionProxyConfigServiceClient::SetConfigRefreshTimer(
       &DataReductionProxyConfigServiceClient::RetrieveConfig);
 }
 
-base::Time DataReductionProxyConfigServiceClient::Now() const {
+base::Time DataReductionProxyConfigServiceClient::Now() {
   return base::Time::Now();
 }
 
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.h b/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.h
index e51ea83..8487829 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.h
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.h
@@ -61,7 +61,7 @@ class DataReductionProxyConfigServiceClient {
 
   // Returns the current time.
   // Virtual for testing.
-  virtual base::Time Now() const;
+  virtual base::Time Now();
 
   // Constructs a synthetic response based on |params_|.
   // Virtual for testing.
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_test_utils.cc b/components/data_reduction_proxy/core/browser/data_reduction_proxy_test_utils.cc
index 7aff4be..b3c9c4a 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_test_utils.cc
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_test_utils.cc
@@ -113,7 +113,7 @@ base::TimeDelta TestDataReductionProxyConfigServiceClient::GetDelay() const {
   return config_refresh_timer_.GetCurrentDelay();
 }
 
-base::Time TestDataReductionProxyConfigServiceClient::Now() const {
+base::Time TestDataReductionProxyConfigServiceClient::Now() {
   return tick_clock_.Now();
 }
 
@@ -128,12 +128,12 @@ TestDataReductionProxyConfigServiceClient::TestTickClock::TestTickClock(
 }
 
 base::TimeTicks
-TestDataReductionProxyConfigServiceClient::TestTickClock::NowTicks() const {
+TestDataReductionProxyConfigServiceClient::TestTickClock::NowTicks() {
   return base::TimeTicks::UnixEpoch() + (time_ - base::Time::UnixEpoch());
 }
 
 base::Time
-TestDataReductionProxyConfigServiceClient::TestTickClock::Now() const {
+TestDataReductionProxyConfigServiceClient::TestTickClock::Now() {
   return time_;
 }
 
@@ -142,19 +142,6 @@ void TestDataReductionProxyConfigServiceClient::TestTickClock::SetTime(
   time_ = time;
 }
 
-TestDataReductionProxyConfigServiceClient::TestBackoffEntry::TestBackoffEntry(
-    const net::BackoffEntry::Policy* const policy,
-    const TestTickClock* tick_clock)
-    : net::BackoffEntry(policy),
-      tick_clock_(tick_clock) {
-}
-
-base::TimeTicks
-TestDataReductionProxyConfigServiceClient::TestBackoffEntry::ImplGetTimeNow()
-    const {
-  return tick_clock_->NowTicks();
-}
-
 MockDataReductionProxyService::MockDataReductionProxyService(
     scoped_ptr<DataReductionProxyCompressionStats> compression_stats,
     DataReductionProxySettings* settings,
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_test_utils.h b/components/data_reduction_proxy/core/browser/data_reduction_proxy_test_utils.h
index c7be2e4..b1d29d2 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_test_utils.h
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_test_utils.h
@@ -11,6 +11,8 @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/single_thread_task_runner.h"
+#include "base/time/clock.h"
+#include "base/time/tick_clock.h"
 #include "base/time/time.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_bypass_stats.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.h"
@@ -104,20 +106,20 @@ class TestDataReductionProxyConfigServiceClient
 
  protected:
   // Overrides of DataReductionProxyConfigServiceClient
-  base::Time Now() const override;
+  base::Time Now() override;
   net::BackoffEntry* GetBackoffEntry() override;
 
  private:
   // A clock which returns a fixed value in both base::Time and base::TimeTicks.
-  class TestTickClock {
+  class TestTickClock : public base::Clock, public base::TickClock {
    public:
     TestTickClock(const base::Time& initial_time);
 
-    // Returns the current base::TimeTicks
-    base::TimeTicks NowTicks() const;
+    // base::TickClock implementation.
+    base::TimeTicks NowTicks() override;
 
-    // Returns the current base::Time
-    base::Time Now() const;
+    // base::Clock implementation.
+    base::Time Now() override;
 
     // Sets the current time.
     void SetTime(const base::Time& time);
@@ -126,23 +128,8 @@ class TestDataReductionProxyConfigServiceClient
     base::Time time_;
   };
 
-  // A net::BackoffEntry which uses an injected base::TickClock to control
-  // the backoff expiration time.
-  class TestBackoffEntry : public net::BackoffEntry {
-   public:
-    TestBackoffEntry(const BackoffEntry::Policy* const policy,
-                     const TestTickClock* tick_clock);
-
-   protected:
-    // Override of net::BackoffEntry.
-    base::TimeTicks ImplGetTimeNow() const override;
-
-   private:
-    const TestTickClock* tick_clock_;
-  };
-
   TestTickClock tick_clock_;
-  TestBackoffEntry test_backoff_entry_;
+  net::BackoffEntry test_backoff_entry_;
 };
 
 // Test version of |DataReductionProxyService|, which permits mocking of various