Adding shutdown tracing capabilities

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index 25213153b31fd20322157d183e206643ec9dfa08..f0dd21551514f6ae1321a8cbae0abb149912798e 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -793,6 +793,20 @@ const char kTestingFixedHttpsPort[]         = "testing-fixed-https-port";
 // Runs the security test for the renderer sandbox.
 const char kTestSandbox[]                   = "test-sandbox";
 
+// Causes TRACE_EVENT flags to be recorded beginning with shutdown. Optionally,
+// can specify the specific trace categories to include (e.g.
+// --trace-shutdown=base,net) otherwise, all events are recorded. Setting this
+// flag results in the first call to BeginTracing() to receive all trace events

[James Cook, 2013/08/30 22:54:02]

Is the part of the comment about BeginTracing() accurate?

[Mr4D (OOO till 08-26), 2013/08/31 02:03:44]

Done.

+// since startup. In Chrome, you may find --trace-shutdown-file to control the
+// auto-saving of the trace (not supported in the base-only TraceLog component).
+const char kTraceShutdown[]                 = "trace-shutdown";
+
+// If supplied, sets the file which shutdown tracing will be stored into, if
+// omitted the default will be used "chrometrace.log" in the current directory.

[James Cook, 2013/08/30 22:54:02]

Update this to match the other filename if you change it

[Mr4D (OOO till 08-26), 2013/08/31 02:03:44]

Somehow .json for logfiles makes no sense. ".json" is a javascript exchange
format which makes every programmer think that it must have something to do with
with some Javascript program - bit surely not with a log file. Since the startup
default name is also .log - this should also remain this way.

+// Has no effect unless --trace-shutdown is also supplied.
+// Example: --trace-shutdown --trace-shutdown-file=/tmp/trace_event.log
+const char kTraceShutdownFile[]             = "trace-shutdown-file";
+
 // Causes TRACE_EVENT flags to be recorded from startup. Optionally, can
 // specify the specific trace categories to include (e.g.
 // --trace-startup=base,net) otherwise, all events are recorded. Setting this