Make the launch params the default client behavior for UMA 3g

components/metrics/metrics_service.cc

Index: components/metrics/metrics_service.cc
diff --git a/components/metrics/metrics_service.cc b/components/metrics/metrics_service.cc
index 7e31ddb93156bf301ef333bd5cbe71bb7acc9691..e1a30b007ecb0c4de0d8bde11f0864be838c7284 100644
--- a/components/metrics/metrics_service.cc
+++ b/components/metrics/metrics_service.cc
@@ -200,6 +200,9 @@ const size_t kUploadLogAvoidRetransmitSize = 100 * 1024;
 // Interval, in minutes, between state saves.
 const int kSaveStateIntervalMinutes = 5;
 
+// Default sampling rate for UMA log uploads
+const int kDefaultSamplingProbability = 100;
+
 enum ResponseStatus {
   UNKNOWN_FAILURE,
   SUCCESS,
@@ -235,12 +238,17 @@ void MarkAppCleanShutdownAndCommit(CleanExitBeacon* clean_exit_beacon,
 // Determines if current log should be sent based on sampling rate. Returns true
 // if the sampling rate is not set.
 bool ShouldUploadLog() {
+  std::string experiment_group =
+      base::FieldTrialList::FindFullName("UMA_EnableCellularLogUpload");
+  if (experiment_group.empty())
+    return true;
+
   std::string probability_str = variations::GetVariationParamValue(
       "UMA_EnableCellularLogUpload", "Sample_Probability");
+  int probability;
   if (probability_str.empty())
-    return true;
+    probability = kDefaultSamplingProbability;
 
-  int probability;
   // In case specified sampling rate is invalid.
   if (!base::StringToInt(probability_str, &probability))
     return true;