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

components/variations/processed_study.cc

Index: components/variations/processed_study.cc
diff --git a/components/variations/processed_study.cc b/components/variations/processed_study.cc
index 9d0e4f14d512dbda40a6fda36a672a178e1257b0..88e572d654aad01fadc8d629934e3ea86fcf08dd 100644
--- a/components/variations/processed_study.cc
+++ b/components/variations/processed_study.cc
@@ -5,6 +5,7 @@
 #include "components/variations/processed_study.h"
 
 #include <set>
+#include <string>
 
 #include "base/version.h"
 #include "components/variations/proto/study.pb.h"
@@ -91,6 +92,16 @@ bool ProcessedStudy::Init(const Study* study, bool is_expired) {
   return true;
 }
 
+int ProcessedStudy::GetExperimentIndexByName(
+    const std::string& name) const {
+  for (int i = 0; i < study_->experiment_size(); ++i) {
+    if (study_->experiment(i).name() == name)
+      return i;
+  }
+
+  return -1;
+}
+
 // static
 bool ProcessedStudy::ValidateAndAppendStudy(
     const Study* study,