Add TRACE_EVENT macros to net.

net/proxy/proxy_resolver_v8_tracing.cc

Index: net/proxy/proxy_resolver_v8_tracing.cc
diff --git a/net/proxy/proxy_resolver_v8_tracing.cc b/net/proxy/proxy_resolver_v8_tracing.cc
index a9fdeeb771db19ae5e9ea4dbbcb83c0bdbac3b95..8addec73f20c6a332bf3e19f9573c4b259fb5108 100644
--- a/net/proxy/proxy_resolver_v8_tracing.cc
+++ b/net/proxy/proxy_resolver_v8_tracing.cc
@@ -20,6 +20,7 @@
 #include "base/thread_task_runner_handle.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
+#include "base/trace_event/trace_event.h"
 #include "net/base/address_list.h"
 #include "net/base/net_errors.h"
 #include "net/base/network_interfaces.h"
@@ -578,6 +579,7 @@ void Job::ExecuteNonBlocking() {
 }
 
 int Job::ExecuteProxyResolver() {
+  TRACE_EVENT0("v8", "Job::ExecuteProxyResolver");

[mmenke, 2016/04/04 16:45:49]

Is v8 the right label for net code?  Yes, we are just running v8 here, not sure
about tracing names in general.

[ssid, 2016/04/05 00:50:13]

Sorry I missed this one. The name is generally the namespace of the function.
But when it is not strict. Changed it to net to stick to namespace in this case.

   int result = ERR_UNEXPECTED;  // Initialized to silence warnings.
 
   switch (operation_) {