Revert 84197 - Add one-time randomization support for FieldTrial, and the ability to

disable field trials. I am going to have a need for both soon.

Cleaning up some comments about empty trial names, adding static
method TrialExists() and simplifying many call sites by using this
method.

While I'm in there and needing base/OWNERS approval, add an OWNERS
file for base/metrics that adds jar@chromium.org as an owner for that
directory.

BUG=none
TEST=base_unittests
TBR=jam@chromium.org
R=jar@chromium.org,phajdan.jr@chromium.org,mark@chromium.org,wtc@chromium.org

Reason for revert:  See http://crbug.com/81750

BUG=81750
TBR=joi@chromium.org
Review URL: http://codereview.chromium.org/6931048

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@84373 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 26 insertions, 17 deletions

diff --git a/net/base/host_resolver_impl.cc b/net/base/host_resolver_impl.cc
index 8c9d17f..8b33229 100644
--- a/net/base/host_resolver_impl.cc
+++ b/net/base/host_resolver_impl.cc
@@ -554,8 +554,9 @@ class HostResolverImpl::Job
 
     UMA_HISTOGRAM_ENUMERATION("DNS.ResolveCategory", category, RESOLVE_MAX);
 
-    static const bool show_speculative_experiment_histograms =
-        base::FieldTrialList::TrialExists("DnsImpact");
+    static bool show_speculative_experiment_histograms =
+        base::FieldTrialList::Find("DnsImpact") &&
+        !base::FieldTrialList::Find("DnsImpact")->group_name().empty();
     if (show_speculative_experiment_histograms) {
       UMA_HISTOGRAM_ENUMERATION(
           base::FieldTrial::MakeName("DNS.ResolveCategory", "DnsImpact"),
@@ -565,8 +566,9 @@ class HostResolverImpl::Job
                                                  "DnsImpact"), duration);
       }
     }
-    static const bool show_parallelism_experiment_histograms =
-        base::FieldTrialList::TrialExists("DnsParallelism");
+    static bool show_parallelism_experiment_histograms =
+        base::FieldTrialList::Find("DnsParallelism") &&
+        !base::FieldTrialList::Find("DnsParallelism")->group_name().empty();
     if (show_parallelism_experiment_histograms) {
       UMA_HISTOGRAM_ENUMERATION(
           base::FieldTrial::MakeName("DNS.ResolveCategory", "DnsParallelism"),
diff --git a/net/http/http_cache_transaction.cc b/net/http/http_cache_transaction.cc
index c8b2b33..ec7561b 100644
--- a/net/http/http_cache_transaction.cc
+++ b/net/http/http_cache_transaction.cc
@@ -870,7 +870,8 @@ int HttpCache::Transaction::DoAddToEntryComplete(int result) {
       base::TimeTicks::Now() - entry_lock_waiting_since_;
   UMA_HISTOGRAM_TIMES("HttpCache.EntryLockWait", entry_lock_wait);
   static const bool prefetching_fieldtrial =
-      base::FieldTrialList::TrialExists("Prefetch");
+      base::FieldTrialList::Find("Prefetch") &&
+      !base::FieldTrialList::Find("Prefetch")->group_name().empty();
   if (prefetching_fieldtrial) {
     UMA_HISTOGRAM_TIMES(
         base::FieldTrial::MakeName("HttpCache.EntryLockWait", "Prefetch"),
diff --git a/net/http/http_network_transaction.cc b/net/http/http_network_transaction.cc
index f298679..5cd2f92 100644
--- a/net/http/http_network_transaction.cc
+++ b/net/http/http_network_transaction.cc
@@ -1010,8 +1010,9 @@ void HttpNetworkTransaction::LogTransactionConnectedMetrics() {
         base::TimeDelta::FromMilliseconds(1), base::TimeDelta::FromMinutes(10),
         100);
 
-  static const bool use_conn_impact_histogram =
-      base::FieldTrialList::TrialExists("ConnCountImpact");
+  static bool use_conn_impact_histogram(
+      base::FieldTrialList::Find("ConnCountImpact") &&
+      !base::FieldTrialList::Find("ConnCountImpact")->group_name().empty());
   if (use_conn_impact_histogram) {
     UMA_HISTOGRAM_CLIPPED_TIMES(
         base::FieldTrial::MakeName("Net.Transaction_Connected_New",
@@ -1022,8 +1023,8 @@ void HttpNetworkTransaction::LogTransactionConnectedMetrics() {
     }
   }
 
-  static const bool use_spdy_histogram =
-      base::FieldTrialList::TrialExists("SpdyImpact");
+  static bool use_spdy_histogram(base::FieldTrialList::Find("SpdyImpact") &&
+      !base::FieldTrialList::Find("SpdyImpact")->group_name().empty());
   if (use_spdy_histogram && response_.was_npn_negotiated) {
     UMA_HISTOGRAM_CLIPPED_TIMES(
       base::FieldTrial::MakeName("Net.Transaction_Connected_Under_10",
diff --git a/net/socket/client_socket_pool_histograms.cc b/net/socket/client_socket_pool_histograms.cc
index 5c3bddb..202112b 100644
--- a/net/socket/client_socket_pool_histograms.cc
+++ b/net/socket/client_socket_pool_histograms.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -58,8 +58,10 @@ void ClientSocketPoolHistograms::AddSocketType(int type) const {
 void ClientSocketPoolHistograms::AddRequestTime(base::TimeDelta time) const {
   request_time_->AddTime(time);
 
-  static const bool proxy_connection_impact_trial_exists =
-      base::FieldTrialList::TrialExists("ProxyConnectionImpact");
+  static bool proxy_connection_impact_trial_exists(
+      base::FieldTrialList::Find("ProxyConnectionImpact") &&
+      !base::FieldTrialList::Find("ProxyConnectionImpact")->
+          group_name().empty());
   if (proxy_connection_impact_trial_exists && is_http_proxy_connection_) {
     UMA_HISTOGRAM_CUSTOM_TIMES(
         base::FieldTrial::MakeName("Net.HttpProxySocketRequestTime",
diff --git a/net/socket/ssl_client_socket_pool.cc b/net/socket/ssl_client_socket_pool.cc
index 7bde6d0..5f8daa7 100644
--- a/net/socket/ssl_client_socket_pool.cc
+++ b/net/socket/ssl_client_socket_pool.cc
@@ -347,8 +347,9 @@ int SSLConnectJob::DoSSLConnectComplete(int result) {
                                    100);
       }
 
-      static const bool false_start_trial =
-          base::FieldTrialList::TrialExists("SSLFalseStart");
+      static bool false_start_trial(
+          base::FieldTrialList::Find("SSLFalseStart") &&
+          !base::FieldTrialList::Find("SSLFalseStart")->group_name().empty());
       if (false_start_trial) {
         UMA_HISTOGRAM_CUSTOM_TIMES(base::FieldTrial::MakeName(
                                        "Net.SSL_Connection_Latency",
diff --git a/net/socket/stream_socket.cc b/net/socket/stream_socket.cc
index 3ef24c0..37482b4 100644
--- a/net/socket/stream_socket.cc
+++ b/net/socket/stream_socket.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -134,7 +134,8 @@ void StreamSocket::UseHistory::EmitPreconnectionHistograms() const {
   UMA_HISTOGRAM_ENUMERATION("Net.PreconnectUtilization2", result, 9);
 
   static const bool connect_backup_jobs_fieldtrial =
-      base::FieldTrialList::TrialExists("ConnnectBackupJobs");
+      base::FieldTrialList::Find("ConnnectBackupJobs") &&
+      !base::FieldTrialList::Find("ConnnectBackupJobs")->group_name().empty();
   if (connect_backup_jobs_fieldtrial) {
     UMA_HISTOGRAM_ENUMERATION(
         base::FieldTrial::MakeName("Net.PreconnectUtilization2",
diff --git a/net/url_request/url_request_http_job.cc b/net/url_request/url_request_http_job.cc
index 8504260..95ea53c 100644
--- a/net/url_request/url_request_http_job.cc
+++ b/net/url_request/url_request_http_job.cc
@@ -1127,7 +1127,8 @@ void URLRequestHttpJob::RecordTimer() {
   request_creation_time_ = base::Time();
 
   static const bool use_prefetch_histogram =
-      base::FieldTrialList::TrialExists("Prefetch");
+      base::FieldTrialList::Find("Prefetch") &&
+      !base::FieldTrialList::Find("Prefetch")->group_name().empty();
 
   UMA_HISTOGRAM_MEDIUM_TIMES("Net.HttpTimeToFirstByte", to_start);
   if (use_prefetch_histogram) {