Make MetricsService upload logs through an interface.

components/metrics/net/net_metrics_log_uploader.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/net/net_metrics_log_uploader.h"
+
+#include "base/metrics/histogram.h"
+#include "components/metrics/net/compression_utils.h"
+#include "net/base/load_flags.h"
+#include "net/url_request/url_fetcher.h"
+#include "url/gurl.h"
+
+namespace metrics {
+
+NetMetricsLogUploader::NetMetricsLogUploader(
+    net::URLRequestContextGetter* request_context_getter,
+    const std::string& server_url,
+    const std::string& mime_type,
+    const base::Callback<void(int)> on_upload_complete)
+    : request_context_getter_(request_context_getter),
+      server_url_(server_url),
+      mime_type_(mime_type),
+      on_upload_complete_(on_upload_complete) {
+}
+
+NetMetricsLogUploader::~NetMetricsLogUploader() {
+}
+
+bool NetMetricsLogUploader::UploadLog(const std::string& log_data,
+                                      const std::string& log_hash) {
+  std::string compressed_log_text;
+  if (!GzipCompress(log_data, &compressed_log_text)) {
+    NOTREACHED();
+    return false;
+  }
+
+  UMA_HISTOGRAM_PERCENTAGE(
+      "UMA.ProtoCompressionRatio",
+      100 * compressed_log_text.size() / log_data.size());
+  UMA_HISTOGRAM_CUSTOM_COUNTS(
+      "UMA.ProtoGzippedKBSaved",
+      (log_data.size() - compressed_log_text.size()) / 1024,
+      1, 2000, 50);
+
+  current_fetch_.reset(
+      net::URLFetcher::Create(GURL(server_url_), net::URLFetcher::POST, this));
+  current_fetch_->SetRequestContext(request_context_getter_);
+  current_fetch_->SetUploadData(mime_type_, compressed_log_text);
+
+  // Tell the server that we're uploading gzipped protobufs.
+  current_fetch_->SetExtraRequestHeaders("content-encoding: gzip");
+
+  DCHECK(!log_hash.empty());
+  current_fetch_->AddExtraRequestHeader("X-Chrome-UMA-Log-SHA1: " + log_hash);
+
+  // We already drop cookies server-side, but we might as well strip them out
+  // client-side as well.
+  current_fetch_->SetLoadFlags(net::LOAD_DO_NOT_SAVE_COOKIES |
+                               net::LOAD_DO_NOT_SEND_COOKIES);
+  return true;
+}
+
+void NetMetricsLogUploader::OnURLFetchComplete(const net::URLFetcher* source) {
+  // We're not allowed to re-use the existing |URLFetcher|s, so free them here.
+  // Note however that |source| is aliased to the fetcher, so we should be
+  // careful not to delete it too early.
+  DCHECK_EQ(current_fetch_.get(), source);
+  scoped_ptr<net::URLFetcher> fetch(current_fetch_.Pass());

[blundell, 2014/05/26 07:56:56]

nit: This is pretty bizarre code. Why not just do a current_fetch_.reset();
after line 73?

[Alexei Svitkine (slow), 2014/05/26 20:04:10]

Done. I had copied the pattern from the previous code, but I agree that a
.reset() at the end is simpler.

+
+  int response_code = source->GetResponseCode();
+  if (response_code == net::URLFetcher::RESPONSE_CODE_INVALID)
+    response_code = -1;
+  on_upload_complete_.Run(response_code);
+}
+
+}  // namespace metrics