Add support for variations controlled overriding UI strings to the variations service.

components/variations/variations_seed_processor.cc

Index: components/variations/variations_seed_processor.cc
diff --git a/components/variations/variations_seed_processor.cc b/components/variations/variations_seed_processor.cc
index e468e4e2d808cddef99f84c3c6414a3a1205eeb0..1bd502a6d963cbbb3d192a1d1dde835081cd0d12 100644
--- a/components/variations/variations_seed_processor.cc
+++ b/components/variations/variations_seed_processor.cc
@@ -8,6 +8,7 @@
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
+#include "base/strings/utf_string_conversions.h"
 #include "components/variations/processed_study.h"
 #include "components/variations/study_filtering.h"
 #include "components/variations/variations_associated_data.h"
@@ -58,6 +59,17 @@ void RegisterVariationIds(const Study_Experiment& experiment,
   }
 }
 
+void ApplyUIStringOverrides(

[Alexei Svitkine (slow), 2014/07/04 15:48:51]

Add a comment please.

[jwd, 2014/07/07 15:52:20]

Done.

+    const Study_Experiment& experiment,
+    const VariationsSeedProcessor::UIStringOverrideCallback& override_string) {
+  for (int i = 0; i < experiment.override_ui_string_size(); ++i) {
+    Study_Experiment_OverrideUIString  experiment_overrides =

[Alexei Svitkine (slow), 2014/07/03 17:54:40]

Nit: Remove extra space.

[jwd, 2014/07/07 15:52:20]

Done.

+        experiment.override_ui_string(i);
+    override_string.Run(experiment_overrides.name_hash(),
+                        base::ASCIIToUTF16(experiment_overrides.value()));

[Alexei Svitkine (slow), 2014/07/03 17:54:41]

The value may not be ascii. Use UTF8ToUTF16.

[jwd, 2014/07/07 15:52:20]

Done.

+  }
+}
+
 }  // namespace
 
 VariationsSeedProcessor::VariationsSeedProcessor() {
@@ -73,17 +85,19 @@ void VariationsSeedProcessor::CreateTrialsFromSeed(
     const base::Version& version,
     Study_Channel channel,
     Study_FormFactor form_factor,
-    const std::string& hardware_class) {
+    const std::string& hardware_class,
+    const UIStringOverrideCallback& override_string) {
   std::vector<ProcessedStudy> filtered_studies;
   FilterAndValidateStudies(seed, locale, reference_date, version, channel,
                            form_factor, hardware_class, &filtered_studies);
 
   for (size_t i = 0; i < filtered_studies.size(); ++i)
-    CreateTrialFromStudy(filtered_studies[i]);
+    CreateTrialFromStudy(filtered_studies[i], override_string);
 }
 
 void VariationsSeedProcessor::CreateTrialFromStudy(
-    const ProcessedStudy& processed_study) {
+    const ProcessedStudy& processed_study,
+    const UIStringOverrideCallback& override_string) {
   const Study& study = *processed_study.study();
 
   // Check if any experiments need to be forced due to a command line
@@ -98,8 +112,11 @@ void VariationsSeedProcessor::CreateTrialFromStudy(
                                                  experiment.name()));
       RegisterExperimentParams(study, experiment);
       RegisterVariationIds(experiment, study.name());
-      if (study.activation_type() == Study_ActivationType_ACTIVATION_AUTO)
+      if (study.activation_type() == Study_ActivationType_ACTIVATION_AUTO) {
         trial->group();
+        // UI Strings can only be overridden from ACTIVATION_AUTO experiments.
+        ApplyUIStringOverrides(experiment, override_string);
+      }
 
       DVLOG(1) << "Trial " << study.name() << " forced by flag: "
                << experiment.forcing_flag();
@@ -145,8 +162,18 @@ void VariationsSeedProcessor::CreateTrialFromStudy(
   trial->SetForced();
   if (processed_study.is_expired())

[Alexei Svitkine (slow), 2014/07/04 15:48:51]

Nit: Add {}'s here.

[jwd, 2014/07/07 15:52:20]

Done.

     trial->Disable();
-  else if (study.activation_type() == Study_ActivationType_ACTIVATION_AUTO)
-    trial->group();
+  else if (study.activation_type() == Study_ActivationType_ACTIVATION_AUTO) {
+    const std::string& group_name = trial->group_name();
+
+    // UI Strings can only be overridden from ACTIVATION_AUTO experiments.
+    int experiment_index = processed_study.GetExperimentIndexByName(group_name);

[Alexei Svitkine (slow), 2014/07/04 15:48:51]

Maybe add a bool to keep track if any experiment had UI string overrides (via
the loop above) and do an early return if they haven't - to avoid this extra
work unless necessary.

[jwd, 2014/07/07 15:52:20]

Done.

+
+    // The field trial was defined from |study|, so the active experiment's name
+    // must be in the |study|.
+    DCHECK_GE(experiment_index, 0);

[Alexei Svitkine (slow), 2014/07/04 15:48:52]

Change to NE(-1, 

[jwd, 2014/07/07 15:52:20]

Done.

+
+    ApplyUIStringOverrides(study.experiment(experiment_index), override_string);
+  }
 }
 
 }  // namespace chrome_variations