Refactoring AudioDirectiveHandler to support testing

components/copresence/handlers/audio/audio_directive_list.cc

Index: components/copresence/handlers/audio/audio_directive_list.cc
diff --git a/components/copresence/handlers/audio/audio_directive_list.cc b/components/copresence/handlers/audio/audio_directive_list.cc
index 5434c60b4ea0185df238cda87d4bc94cfdc15e0a..a12cbc27124535d4911bfdad2b2b0567eec9058f 100644
--- a/components/copresence/handlers/audio/audio_directive_list.cc
+++ b/components/copresence/handlers/audio/audio_directive_list.cc
@@ -4,40 +4,28 @@
 
 #include "components/copresence/handlers/audio/audio_directive_list.h"
 
-#include "base/bind.h"
-#include "base/logging.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/time/default_tick_clock.h"
-#include "base/time/time.h"
-#include "components/copresence/handlers/audio/tick_clock_ref_counted.h"
-
 namespace copresence {
 
-// Public methods.
+// Public functions.
 
-AudioDirective::AudioDirective() {
-}
+AudioDirective::AudioDirective() {}
 
 AudioDirective::AudioDirective(const std::string& op_id,
                                base::TimeTicks end_time)
-    : op_id(op_id), end_time(end_time) {
-}
+    : op_id(op_id), end_time(end_time) {}
 
-AudioDirectiveList::AudioDirectiveList()
-    : clock_(new TickClockRefCounted(
-          make_scoped_ptr(new base::DefaultTickClock))) {
-}
+AudioDirectiveList::AudioDirectiveList(
+    const scoped_refptr<TickClockRefCounted>& clock)
+    : clock_(clock) {}
 
-AudioDirectiveList::~AudioDirectiveList() {
-}
+AudioDirectiveList::~AudioDirectiveList() {}
 
 void AudioDirectiveList::AddDirective(const std::string& op_id,
                                       base::TimeDelta ttl) {
   base::TimeTicks end_time = clock_->NowTicks() + ttl;
 
-  // In case this op is already in the list, update it instead of adding
-  // it again.
-  std::vector<AudioDirective>::iterator it = FindDirectiveByOpId(op_id);
+  // If this op is already in the list, update it instead of adding it again.
+  auto it = FindDirectiveByOpId(op_id);
   if (it != active_directives_.end()) {
     it->end_time = end_time;
     std::make_heap(active_directives_.begin(),
@@ -53,7 +41,7 @@ void AudioDirectiveList::AddDirective(const std::string& op_id,
 }
 
 void AudioDirectiveList::RemoveDirective(const std::string& op_id) {
-  std::vector<AudioDirective>::iterator it = FindDirectiveByOpId(op_id);
+  auto it = FindDirectiveByOpId(op_id);
   if (it != active_directives_.end())
     active_directives_.erase(it);
 
@@ -63,30 +51,24 @@ void AudioDirectiveList::RemoveDirective(const std::string& op_id) {
 }
 
 scoped_ptr<AudioDirective> AudioDirectiveList::GetActiveDirective() {
-  // The top is always the instruction that is ending the latest. If that time
-  // has passed, means all our previous instructions have expired too, hence
-  // clear the list.
-  if (!active_directives_.empty() &&
+  // The top is always the instruction that is ending the latest.
+  // If that time has passed, all our previous instructions have expired too.
+  // So we clear the list.
+  if (active_directives_.empty() ||
       active_directives_.front().end_time < clock_->NowTicks()) {
     active_directives_.clear();
-  }
-
-  if (active_directives_.empty())
     return scoped_ptr<AudioDirective>().Pass();
+  }
 
   return make_scoped_ptr(new AudioDirective(active_directives_.front()));
 }
 
-void AudioDirectiveList::set_clock_for_testing(
-    const scoped_refptr<TickClockRefCounted>& clock) {
-  clock_ = clock;
-}
 
-// Private methods.
+// Private functions.
 
 std::vector<AudioDirective>::iterator AudioDirectiveList::FindDirectiveByOpId(
     const std::string& op_id) {
-  for (std::vector<AudioDirective>::iterator it = active_directives_.begin();
+  for (auto it = active_directives_.begin();
        it != active_directives_.end();
        ++it) {
     if (it->op_id == op_id)