Change the logic for discarding all non-histogram logs because of actions/omnibox events to truncat…

components/metrics/metrics_log.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/metrics/metrics_log.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 24 matching lines @@
 
 #if defined(OS_WIN)
 #include "base/win/current_module.h"
 #endif
 
 using base::SampleCountIterator;
 typedef variations::ActiveGroupId ActiveGroupId;
 
 namespace metrics {
 
+namespace internal {
+// Maximum number of events before truncation.
+extern const int kOmniboxEventLimit = 5000;
+extern const int kUserActionEventLimit = 5000;
+}
+
 namespace {
 
 // Any id less than 16 bytes is considered to be a testing id.
 bool IsTestingID(const std::string& id) {
   return id.size() < 16;
 }
 
 void WriteFieldTrials(const std::vector<ActiveGroupId>& field_trial_ids,
                       SystemProfileProto* system_profile) {
   for (std::vector<ActiveGroupId>::const_iterator it =
@@ skipping 261 matching lines @@
   if (success)
     *app_version = system_profile->app_version();
   return success;
 }
 
 void MetricsLog::CloseLog() {
   DCHECK(!closed_);
   closed_ = true;
 }
 
+void MetricsLog::TruncateEvents() {
+  DCHECK(!closed_);
+  if (uma_proto_.user_action_event_size() > internal::kUserActionEventLimit) {
+    UMA_HISTOGRAM_COUNTS_100000("UMA.TruncatedEvents.UserAction",
+                                uma_proto_.user_action_event_size());
+    uma_proto_.mutable_user_action_event()->DeleteSubrange(
+        internal::kUserActionEventLimit,
+        uma_proto_.user_action_event_size() - internal::kUserActionEventLimit);
+  }
+
+  if (uma_proto_.omnibox_event_size() > internal::kOmniboxEventLimit) {
+    UMA_HISTOGRAM_COUNTS_100000("UMA.TruncatedEvents.Omnibox",
+                                uma_proto_.omnibox_event_size());
+    uma_proto_.mutable_omnibox_event()->DeleteSubrange(
+        internal::kOmniboxEventLimit,
+        uma_proto_.omnibox_event_size() - internal::kOmniboxEventLimit);
+  }
+}
+
 void MetricsLog::GetEncodedLog(std::string* encoded_log) {
   DCHECK(closed_);
   uma_proto_.SerializeToString(encoded_log);
 }
 
 }  // namespace metrics