C++ Readability review for holte

components/rappor/rappor_service.cc

Index: components/rappor/rappor_service.cc
diff --git a/components/rappor/rappor_service.cc b/components/rappor/rappor_service.cc
index 493e7b9d2ccafbf716306181c05f47df680c83bb..38d75a0aba4a8202f1369a0e58bc08747e1f6cf4 100644
--- a/components/rappor/rappor_service.cc
+++ b/components/rappor/rappor_service.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// Change for readability
+
 #include "components/rappor/rappor_service.h"
 
 #include "base/base64.h"
@@ -42,13 +44,13 @@ GURL GetServerUrl() {
 }
 
 const RapporParameters kRapporParametersForType[NUM_RAPPOR_TYPES] = {
-    {  // ETLD_PLUS_ONE_RAPPOR_TYPE
-        16 /* Bloom filter size bytes */,
-        2 /* Bloom filter hash count */,
-        rappor::PROBABILITY_75 /* Fake data probability */,
-        rappor::PROBABILITY_50 /* Fake one probability */,
-        rappor::PROBABILITY_75 /* One coin probability */,
-        rappor::PROBABILITY_50 /* Zero coin probability */
+    {// ETLD_PLUS_ONE_RAPPOR_TYPE
+     16 /* Bloom filter size bytes */,
+     2 /* Bloom filter hash count */,
+     rappor::PROBABILITY_75 /* Fake data probability */,
+     rappor::PROBABILITY_50 /* Fake one probability */,
+     rappor::PROBABILITY_75 /* One coin probability */,
+     rappor::PROBABILITY_50 /* Zero coin probability */
     },
 };
 
@@ -98,11 +100,14 @@ void RapporService::RegisterPrefs(PrefRegistrySimple* registry) {
 }
 
 void RapporService::LoadCohort(PrefService* pref_service) {
-  DCHECK_EQ(cohort_, -1);
+  DCHECK(!IsInitialized());
   cohort_ = pref_service->GetInteger(prefs::kRapporCohort);
+  // If the user is already assigned to a valid cohort, we're done.
   if (cohort_ >= 0 && cohort_ < kNumCohorts)
     return;
 
+  // This is the first time the client has started the service (or thier

[ktl, 2014/03/18 08:35:01]

Spelling: their

[Steven Holte, 2014/03/19 23:46:55]

Done.

+  // preferences were corrupted).  Randomly assign them to a cohort.
   cohort_ = base::RandGenerator(kNumCohorts);
   pref_service->SetInteger(prefs::kRapporCohort, cohort_);
 }
@@ -132,7 +137,8 @@ bool RapporService::ExportMetrics(RapporReports* reports) {
   DCHECK_GE(cohort_, 0);
   reports->set_cohort(cohort_);
 
-  for (std::map<std::string, RapporMetric*>::iterator it = metrics_map_.begin();
+  for (std::map<std::string, RapporMetric*>::const_iterator it =
+          metrics_map_.begin();

[ktl, 2014/03/18 08:35:01]

This would need one more space; the four space indentation is counted from the
left parenthesis. (Clang-format also does this.)

[Steven Holte, 2014/03/19 23:46:55]

Done.

        metrics_map_.end() != it;

[ktl, 2014/03/18 08:35:01]

I've not seen this style (putting the variable iterator to the right in
comparison) before, is this also project-specific?

Note that Chromium style guide prefers foo == 0 to 0 == foo.

[Steven Holte, 2014/03/19 23:46:55]

base/metrics/... seems to use that style in a few places, but I think that is
not the norm in chrome code.  Fixed.

        ++it) {
     const RapporMetric* metric = it->second;
@@ -163,7 +169,6 @@ void RapporService::RecordSampleInternal(const std::string& metric_name,
                                          const RapporParameters& parameters,
                                          const std::string& sample) {
   DCHECK(IsInitialized());
-
   RapporMetric* metric = LookUpMetric(metric_name, parameters);
   metric->AddSample(sample);
 }
@@ -171,7 +176,7 @@ void RapporService::RecordSampleInternal(const std::string& metric_name,
 RapporMetric* RapporService::LookUpMetric(const std::string& metric_name,
                                           const RapporParameters& parameters) {
   DCHECK(IsInitialized());
-  std::map<std::string, RapporMetric*>::iterator it =
+  std::map<std::string, RapporMetric*>::const_iterator it =
       metrics_map_.find(metric_name);
   if (metrics_map_.end() != it) {
     RapporMetric* metric = it->second;