Remove NO_LOG LogType enum value.

Also, changes a condition to a switch to
make compiler warn if a new enum value is
added.

BUG=none

Review URL: https://codereview.chromium.org/310483009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@274582 0039d316-1c4b-4281-b951-d872f2087c98

components/metrics/metrics_log_base.cc

@@ -37,7 +37,6 @@ MetricsLogBase::MetricsLogBase(const std::string& client_id,
                                const std::string& version_string)
     : locked_(false),
       log_type_(log_type) {
-  DCHECK_NE(NO_LOG, log_type);
   if (IsTestingID(client_id))
     uma_proto_.set_client_id(0);
   else

components/metrics/metrics_log_base.h

@@ -24,11 +24,9 @@ namespace metrics {
 // This class provides base functionality for logging metrics data.
 class MetricsLogBase {
  public:
-  // TODO(asvitkine): Remove the NO_LOG value.
   enum LogType {
     INITIAL_STABILITY_LOG,  // The initial log containing stability stats.
     ONGOING_LOG,            // Subsequent logs in a session.
-    NO_LOG,                 // Placeholder value for when there is no log.
   };
 
   // Creates a new metrics log of the specified type.

components/metrics/metrics_log_manager.cc

@@ -102,12 +102,14 @@ void MetricsLogManager::ResumePausedLog() {
 }
 
 void MetricsLogManager::StoreLog(std::string* log, LogType log_type) {
-  DCHECK_NE(MetricsLogBase::NO_LOG, log_type);
-  metrics::PersistedLogs* destination_queue =
-      (log_type == MetricsLogBase::INITIAL_STABILITY_LOG) ?
-      &initial_log_queue_ : &ongoing_log_queue_;
-
-  destination_queue->StoreLog(log);
+  switch (log_type) {
+    case MetricsLogBase::INITIAL_STABILITY_LOG:
+      initial_log_queue_.StoreLog(log);
+      break;
+    case MetricsLogBase::ONGOING_LOG:
+      ongoing_log_queue_.StoreLog(log);
+      break;
+  }
 }
 
 void MetricsLogManager::StoreStagedLogAsUnsent(