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

net/log/trace_net_log_observer_unittest.cc

Index: net/log/trace_net_log_observer_unittest.cc
diff --git a/net/log/trace_net_log_observer_unittest.cc b/net/log/trace_net_log_observer_unittest.cc
index 2cd4f01a867d41f072a501b9604576fdc5013c28..476db7fba4fe5248bb7c7e446439adb1d3fe006d 100644
--- a/net/log/trace_net_log_observer_unittest.cc
+++ b/net/log/trace_net_log_observer_unittest.cc
@@ -347,6 +347,48 @@ TEST_F(TraceNetLogObserverTest,
   EXPECT_EQ(0u, trace_events()->GetSize());
 }
 
+TEST_F(TraceNetLogObserverTest, DisabledCategoryDoesntEnableNetLog) {
+  // Note: This test and the next one don't use the NetLog instance from the
+  // test fixture as it always has an observer, thus making the return value of
+  // NetLog::IsCapturing() not useful. This is still TEST_F(), as mixing TEST()
+  // and TEST_F() is not allowed.

[xunjieli, 2016/12/05 15:57:04]

This is okay. But alternatively you can use TEST instead of TEST_F under a
different test name. You can have different test names in a single unittest.cc
file. I think it's slightly cleaner that way and the tests are easier to read.

e.g. TEST(TraceNetLogCategoryTest, DisabledCategory)
and TEST(TraceNetLogCategoryTest, EnabledCategory)

[xunjieli, 2016/12/05 16:00:00]

And move these two tests either to the top or after the tests with TEST_F.

[Benoit L, 2016/12/05 16:44:25]

Done.

[Benoit L, 2016/12/05 16:44:25]

Done.

+  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_F(TraceNetLogObserverTest, CanEnableNetLog) {
+  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();
+}
+
 TEST_F(TraceNetLogObserverTest, EventsWithAndWithoutParameters) {
   trace_net_log_observer()->WatchForTraceStart(net_log());
   EnableTraceLog();