When persisting UMA logs to disk, cap log size based on both the XML and protocol buffer logs.

chrome/common/metrics/metrics_log_manager.cc

 // Copyright (c) 2012 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 "chrome/common/metrics/metrics_log_manager.h"
 
 #if defined(USE_SYSTEM_LIBBZ2)
 #include <bzlib.h>
 #else
 #include "third_party/bzip2/bzlib.h"
 #endif
 
+#include <algorithm>
+
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "chrome/common/metrics/metrics_log_base.h"
 
 namespace {
 
 // Used to keep track of discarded protobuf logs without having to track xml and
 // protobuf logs in separate lists.
 const char kDiscardedLog[] = "Log discarded";
 
 }  // anonymous namespace
 
 MetricsLogManager::MetricsLogManager()
     : current_log_type_(NO_LOG),
       paused_log_type_(NO_LOG),
       staged_log_type_(NO_LOG),
       max_ongoing_log_store_size_(0),
       last_provisional_store_index_(-1),
       last_provisional_store_type_(INITIAL_LOG) {}
 
 MetricsLogManager::~MetricsLogManager() {}
 
 bool MetricsLogManager::SerializedLog::empty() const {
   DCHECK_EQ(xml.empty(), proto.empty());
   return xml.empty();
 }
 
+size_t MetricsLogManager::SerializedLog::length() const {
+  return std::max(xml.length(), proto.length());
+}
+
 void MetricsLogManager::SerializedLog::swap(SerializedLog& log) {
   xml.swap(log.xml);
   proto.swap(log.proto);
 }
 
 void MetricsLogManager::BeginLoggingWithLog(MetricsLogBase* log,
                                             LogType log_type) {
   DCHECK(log_type != NO_LOG);
   DCHECK(!current_log_.get());
   current_log_.reset(log);
@@ skipping 205 matching lines @@
     // TODO(jar): See if it would be better to do a CHECK() here.
     return false;
   }
   result = BZ2_bzCompressEnd(&stream);
   DCHECK(result == BZ_OK);
 
   output->resize(stream.total_out_lo32);
 
   return true;
 }