[Metrics] Move CachingPermutedEntropyProvider into the variations component.

components/variations/caching_permuted_entropy_provider.cc

 // Copyright 2013 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 "chrome/common/metrics/caching_permuted_entropy_provider.h"
+#include "components/variations/caching_permuted_entropy_provider.h"
 
 #include <string>
 
 #include "base/base64.h"
 #include "base/logging.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
-#include "chrome/common/pref_names.h"
+#include "components/variations/pref_names.h"
 
 namespace metrics {
 
 CachingPermutedEntropyProvider::CachingPermutedEntropyProvider(
     PrefService* local_state,
     uint16 low_entropy_source,
     size_t low_entropy_source_max)
     : PermutedEntropyProvider(low_entropy_source, low_entropy_source_max),
       local_state_(local_state) {
   ReadFromLocalState();
 }
 
 CachingPermutedEntropyProvider::~CachingPermutedEntropyProvider() {
 }
 
 // static
 void CachingPermutedEntropyProvider::RegisterPrefs(
     PrefRegistrySimple* registry) {
-  registry->RegisterStringPref(prefs::kMetricsPermutedEntropyCache,
+  registry->RegisterStringPref(prefs::kVariationsPermutedEntropyCache,
                                std::string());
 }
 
 // static
 void CachingPermutedEntropyProvider::ClearCache(PrefService* local_state) {
-  local_state->ClearPref(prefs::kMetricsPermutedEntropyCache);
+  local_state->ClearPref(prefs::kVariationsPermutedEntropyCache);
 }
 
 uint16 CachingPermutedEntropyProvider::GetPermutedValue(
     uint32 randomization_seed) const {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   uint16 value = 0;
   if (!FindValue(randomization_seed, &value)) {
     value = PermutedEntropyProvider::GetPermutedValue(randomization_seed);
     AddToCache(randomization_seed, value);
   }
   return value;
 }
 
 void CachingPermutedEntropyProvider::ReadFromLocalState() const {
   const std::string base64_cache_data =
-      local_state_->GetString(prefs::kMetricsPermutedEntropyCache);
+      local_state_->GetString(prefs::kVariationsPermutedEntropyCache);
   std::string cache_data;
   if (!base::Base64Decode(base64_cache_data, &cache_data) ||
       !cache_.ParseFromString(cache_data)) {
-    local_state_->ClearPref(prefs::kMetricsPermutedEntropyCache);
+    local_state_->ClearPref(prefs::kVariationsPermutedEntropyCache);
     NOTREACHED();
   }
 }
 
 void CachingPermutedEntropyProvider::UpdateLocalState() const {
   std::string serialized;
   cache_.SerializeToString(&serialized);
 
   std::string base64_encoded;
   base::Base64Encode(serialized, &base64_encoded);
-  local_state_->SetString(prefs::kMetricsPermutedEntropyCache, base64_encoded);
+  local_state_->SetString(prefs::kVariationsPermutedEntropyCache,
+                          base64_encoded);
 }
 
 void CachingPermutedEntropyProvider::AddToCache(uint32 randomization_seed,
                                                 uint16 value) const {
   PermutedEntropyCache::Entry* entry;
   const int kMaxSize = 25;
   if (cache_.entry_size() >= kMaxSize) {
     // If the cache is full, evict the first entry, swapping later entries in
     // to take its place. This effectively creates a FIFO cache, which is good
     // enough here because the expectation is that there shouldn't be more than
@@ skipping 17 matching lines @@
   for (int i = 0; i < cache_.entry_size(); ++i) {
     if (cache_.entry(i).randomization_seed() == randomization_seed) {
       *value = cache_.entry(i).value();
       return true;
     }
   }
   return false;
 }
 
 }  // namespace metrics