Make MetricsService save compressed logs to local state.

components/metrics/metrics_log_uploader.h

 // 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.
 
 #ifndef COMPONENTS_METRICS_METRICS_LOG_UPLOADER_H_
 #define COMPONENTS_METRICS_METRICS_LOG_UPLOADER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/macros.h"
 
 namespace metrics {
 
 // MetricsLogUploader is an abstract base class for uploading UMA logs on behalf
 // of MetricsService.
 class MetricsLogUploader {
  public:
   // Constructs the uploader that will upload logs to the specified |server_url|
   // with the given |mime_type|. The |on_upload_complete| callback will be
   // called with the HTTP response code of the upload or with -1 on an error.
   MetricsLogUploader(const std::string& server_url,
                      const std::string& mime_type,
                      const base::Callback<void(int)>& on_upload_complete);
   virtual ~MetricsLogUploader();
 
-  // Uploads a log with the specified |log_data| and |log_hash|. |log_hash| is
-  // expected to be the hex-encoded SHA1 hash of |log_data|.
-  virtual bool UploadLog(const std::string& log_data,
+  // Uploads a log with the specified |compressed_log_data| and |log_hash|.
+  // |log_hash| is expected to be the hex-encoded SHA1 hash of the log data
+  // before compression.
+  virtual bool UploadLog(const std::string& compressed_log_data,
                          const std::string& log_hash) = 0;
 
  protected:
   const std::string server_url_;
   const std::string mime_type_;
   const base::Callback<void(int)> on_upload_complete_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MetricsLogUploader);
 };
 
 }  // namespace metrics
 
 #endif  // COMPONENTS_METRICS_METRICS_LOG_UPLOADER_H_