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

chrome/common/metrics/metrics_log_manager.h

 // 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.
 
 #ifndef CHROME_COMMON_METRICS_METRICS_LOG_MANAGER_H_
 #define CHROME_COMMON_METRICS_METRICS_LOG_MANAGER_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 10 matching lines @@
  public:
   MetricsLogManager();
   ~MetricsLogManager();
 
   // Stores both XML and protocol buffer serializations for a log.
   struct SerializedLog {
    public:
     // Exposed to reduce code churn as we transition from the XML pipeline to
     // the protocol buffer pipeline.
     bool empty() const;
+    size_t length() const;
     void swap(SerializedLog& log);
 
     std::string xml;
     std::string proto;
   };
 
   enum LogType {
     INITIAL_LOG,  // The first log of a session.
     ONGOING_LOG,  // Subsequent logs in a session.
     NO_LOG,       // Placeholder value for when there is no log.
@@ skipping 161 matching lines @@
   // This is necessary because during an upload there are two logs (staged
   // and current) and a client might store them in either order, so it's
   // not necessarily the case that the provisional store is the last store.
   int last_provisional_store_index_;
   LogType last_provisional_store_type_;
 
   DISALLOW_COPY_AND_ASSIGN(MetricsLogManager);
 };
 
 #endif  // CHROME_COMMON_METRICS_METRICS_LOG_MANAGER_H_