Refactor field_trial.cc

base/metrics/field_trial.h

 // Copyright (c) 2012 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.
 
 // FieldTrial is a class for handling details of statistical experiments
 // performed by actual users in the field (i.e., in a shipped or beta product).
 // All code is called exclusively on the UI thread currently.
 //
 // The simplest example is an experiment to see whether one of two options
 // produces "better" results across our user population.  In that scenario, UMA
@@ skipping 201 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(FieldTrialTest, Save);
   FRIEND_TEST_ALL_PREFIXES(FieldTrialTest, SaveAll);
   FRIEND_TEST_ALL_PREFIXES(FieldTrialTest, DuplicateRestore);
   FRIEND_TEST_ALL_PREFIXES(FieldTrialTest, SetForcedTurnFeatureOff);
   FRIEND_TEST_ALL_PREFIXES(FieldTrialTest, SetForcedTurnFeatureOn);
   FRIEND_TEST_ALL_PREFIXES(FieldTrialTest, SetForcedChangeDefault_Default);
   FRIEND_TEST_ALL_PREFIXES(FieldTrialTest, SetForcedChangeDefault_NonDefault);
   FRIEND_TEST_ALL_PREFIXES(FieldTrialTest, FloatBoundariesGiveEqualGroupSizes);
   FRIEND_TEST_ALL_PREFIXES(FieldTrialTest, DoesNotSurpassTotalProbability);
 
+  typedef SharedPersistentMemoryAllocator::Reference FieldTrialRef;
+
   friend class base::FieldTrialList;
 
   friend class RefCounted<FieldTrial>;
 
   // This is the group number of the 'default' group when a choice wasn't forced
   // by a call to FieldTrialList::CreateFieldTrial. It is kept private so that
   // consumers don't use it by mistake in cases where the group was forced.
   static const int kDefaultGroupNumber;
 
   // Creates a field trial with the specified parameters. Group assignment will
@@ skipping 83 matching lines @@
   bool forced_;
 
   // Specifies whether the group choice has been reported to observers.
   bool group_reported_;
 
   // Whether this trial is registered with the global FieldTrialList and thus
   // should notify it when its group is queried.
   bool trial_registered_;
 
   // Reference to related field trial struct and data in shared memory.
-  SharedPersistentMemoryAllocator::Reference ref_;
+  FieldTrialRef ref_;
 
   // When benchmarking is enabled, field trials all revert to the 'default'
   // group.
   static bool enable_benchmarking_;
 
   DISALLOW_COPY_AND_ASSIGN(FieldTrial);
 };
 
 //------------------------------------------------------------------------------
 // Class with a list of all active field trials.  A trial is active if it has
 // been registered, which includes evaluating its state based on its probaility.
 // Only one instance of this class exists.
 class BASE_EXPORT FieldTrialList {
  public:
+  typedef SharedPersistentMemoryAllocator FieldTrialAllocator;
+
   // Year that is guaranteed to not be expired when instantiating a field trial
   // via |FactoryGetFieldTrial()|.  Set to two years from the build date.
   static int kNoExpirationYear;
 
   // Observer is notified when a FieldTrial's group is selected.
   class BASE_EXPORT Observer {
    public:
     // Notify observers when FieldTrials's group is selected.
     virtual void OnFieldTrialGroupFinalized(const std::string& trial_name,
                                             const std::string& group_name) = 0;
@@ skipping 183 matching lines @@
   static void NotifyFieldTrialGroupSelection(FieldTrial* field_trial);
 
   // Return the number of active field trials.
   static size_t GetFieldTrialCount();
 
  private:
   // Allow tests to access our innards for testing purposes.
   FRIEND_TEST_ALL_PREFIXES(FieldTrialListTest, InstantiateAllocator);
   FRIEND_TEST_ALL_PREFIXES(FieldTrialListTest, AddTrialsToAllocator);
 
+#if defined(OS_WIN)
+  // Takes in |handle| that should have been retrieved from the command line and
+  // creates a SharedMemoryHandle from it, and then calls
+  // CreateTrialsFromSharedMemory(). Returns true on success, false on failure.
+  static bool CreateTrialsFromWindowsHandle(HANDLE handle);
+#endif
+
   // Expects a mapped piece of shared memory |shm| that was created from the
   // browser process's field_trial_allocator and shared via the command line.
   // This function recreates the allocator, iterates through all the field
   // trials in it, and creates them via CreateFieldTrial(). Returns true if
   // successful and false otherwise.
   static bool CreateTrialsFromSharedMemory(
       std::unique_ptr<base::SharedMemory> shm);
 
   // Instantiate the field trial allocator, add all existing field trials to it,
   // and duplicates its handle to a read-only handle, which gets stored in
@@ skipping 41 matching lines @@
   // one-time randomization is not supported.
   std::unique_ptr<const FieldTrial::EntropyProvider> entropy_provider_;
 
   // List of observers to be notified when a group is selected for a FieldTrial.
   scoped_refptr<ObserverListThreadSafe<Observer> > observer_list_;
 
   // Allocator in shared memory containing field trial data. Used in both
   // browser and child processes, but readonly in the child.
   // In the future, we may want to move this to a more generic place if we want
   // to start passing more data other than field trials.
-  std::unique_ptr<SharedPersistentMemoryAllocator> field_trial_allocator_ =
-      nullptr;
+  std::unique_ptr<FieldTrialAllocator> field_trial_allocator_ = nullptr;
 
 #if defined(OS_WIN)
   // Readonly copy of the handle to the allocator. Needs to be a member variable
   // because it's needed from both CopyFieldTrialStateToFlags() and
   // AppendFieldTrialHandleIfNeeded().
   HANDLE readonly_allocator_handle_ = nullptr;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(FieldTrialList);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_FIELD_TRIAL_H_