Don't compile with TraceLog support on by default.

Don't compile with TraceLog support on by default.

This is just some experimental performance code.  Previously it was creating
a singleton object which created a ProcessMetrics object.  This caused a bunch
of possibly expensive calls to query system information to happen on startup.

[Mark Mentovai, 2009-08-20 01:44:34]

lgtm

http://codereview.chromium.org/174118/diff/1/2
File base/trace_event.h (right):

http://codereview.chromium.org/174118/diff/1/2#newcode32
Line 32: #if 1  // Set to 0 to compile with tracing.
Can we make this something like #ifndef ENABLE_TRACE_EVENT?

http://codereview.chromium.org/174118/diff/1/2#newcode72
Line 72: #endif
Put a comment saying what you're ending, whatever you decide to call it.

[Dean McNamee, 2009-08-20 01:46:20]

I was trying to make it easy to actually turn it on if you wanted to.  If you do
the ifndef, you either have to add a #define, or change the build setup.  I am
ok with that since I never use this code.

On 2009/08/20 01:44:34, Mark Mentovai wrote:
> lgtm
> 
> http://codereview.chromium.org/174118/diff/1/2
> File base/trace_event.h (right):
> 
> http://codereview.chromium.org/174118/diff/1/2#newcode32
> Line 32: #if 1  // Set to 0 to compile with tracing.
> Can we make this something like #ifndef ENABLE_TRACE_EVENT?
> 
> http://codereview.chromium.org/174118/diff/1/2#newcode72
> Line 72: #endif
> Put a comment saying what you're ending, whatever you decide to call it.

[Erik does not do reviews, 2009-08-20 14:54:03]

yeah, I'll go with Mark here too.  If we have a #define, you could put it in
your personal .gypi and not have to worry about accidentally checking in the
file as enabled.

otherwise, LGTM