netlog: Don't enable recording if the "netlog" tracing category is disabled.

net/log/trace_net_log_observer_unittest.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 "net/log/trace_net_log_observer.h"
 
 #include <memory>
 #include <string>
 #include <vector>
 
@@ skipping 380 matching lines @@
 
   std::string item1_params;
   std::string item2_params;
   EXPECT_TRUE(item1->GetString("args.params.foo", &item1_params));
   EXPECT_EQ("bar", item1_params);
 
   EXPECT_TRUE(item2->GetString("args.params", &item2_params));
   EXPECT_TRUE(item2_params.empty());
 }
 
+TEST(TraceNetLogObserverCategoryTest, DisabledCategory) {
+  TraceNetLogObserver observer;
+  NetLog net_log;
+  observer.WatchForTraceStart(&net_log);
+
+  EXPECT_FALSE(net_log.IsCapturing());
+
+  std::string disabled_netlog_category =
+      std::string("-") + kNetLogTracingCategory;
+  TraceLog::GetInstance()->SetEnabled(
+      base::trace_event::TraceConfig(disabled_netlog_category, ""),
+      TraceLog::RECORDING_MODE);
+
+  EXPECT_FALSE(net_log.IsCapturing());
+  observer.StopWatchForTraceStart();
+  EXPECT_FALSE(net_log.IsCapturing());
+
+  TraceLog::GetInstance()->SetDisabled();
+}
+
+TEST(TraceNetLogObserverCategoryTest, EnabledCategory) {
+  TraceNetLogObserver observer;
+  NetLog net_log;
+  observer.WatchForTraceStart(&net_log);
+
+  EXPECT_FALSE(net_log.IsCapturing());
+
+  TraceLog::GetInstance()->SetEnabled(
+      base::trace_event::TraceConfig(kNetLogTracingCategory, ""),
+      TraceLog::RECORDING_MODE);
+
+  EXPECT_TRUE(net_log.IsCapturing());
+  observer.StopWatchForTraceStart();
+  EXPECT_FALSE(net_log.IsCapturing());
+
+  TraceLog::GetInstance()->SetDisabled();
+}
+
 }  // namespace
 
 }  // namespace net