Document the --trace-startup shell flag.

Document the --trace-startup shell flag.

R=ppi@chromium.org, ppi

Committed: https://chromium.googlesource.com/external/mojo/+/94c26b19d3d2580bd41b516b08ddbb1079dfa02b

[ppi, 2015-09-07 08:42:22]

https://codereview.chromium.org/1329963002/diff/1/mojo/devtools/common/README.md
File mojo/devtools/common/README.md (right):

https://codereview.chromium.org/1329963002/diff/1/mojo/devtools/common/README...
mojo/devtools/common/README.md:72: mojo_run --debugger --trace-startup APP_URL
[--android]
You don't actually need --debugger in this case.

[etiennej, 2015-09-07 08:43:52]

https://codereview.chromium.org/1329963002/diff/1/mojo/devtools/common/README.md
File mojo/devtools/common/README.md (right):

https://codereview.chromium.org/1329963002/diff/1/mojo/devtools/common/README...
mojo/devtools/common/README.md:72: mojo_run --debugger --trace-startup APP_URL
[--android]
On 2015/09/07 08:42:21, ppi wrote:
> You don't actually need --debugger in this case.

Done.

[ppi, 2015-09-07 08:56:29]

https://codereview.chromium.org/1329963002/diff/20001/mojo/devtools/common/RE...
File mojo/devtools/common/README.md (right):

https://codereview.chromium.org/1329963002/diff/20001/mojo/devtools/common/RE...
mojo/devtools/common/README.md:72: mojo_run --trace-startup APP_URL [--android]
Actually, this should not be placed under ### Debugger. Debugger offers
interactive tracing, while this is shell feature. Can we put this under ###
Runner?

[etiennej, 2015-09-07 09:05:49]

https://codereview.chromium.org/1329963002/diff/20001/mojo/devtools/common/RE...
File mojo/devtools/common/README.md (right):

https://codereview.chromium.org/1329963002/diff/20001/mojo/devtools/common/RE...
mojo/devtools/common/README.md:72: mojo_run --trace-startup APP_URL [--android]
On 2015/09/07 08:56:29, ppi wrote:
> Actually, this should not be placed under ### Debugger. Debugger offers
> interactive tracing, while this is shell feature. Can we put this under ###
> Runner?

Yet, this is related to tracing, and this sub-section is called "Tracing". Note
that even the "interactive tracing" needs you to run mojo_run with a
tracing-specific argument (by reading the documentation, one would think that
the --debugger flag is only used for tracing).

Do we really want two "tracing" subsections? Shouldn't we have a "### Tracing"
section at the same level than Debugger and Runner?

[etiennej, 2015-09-07 10:41:51]

https://codereview.chromium.org/1329963002/diff/20001/mojo/devtools/common/RE...
File mojo/devtools/common/README.md (right):

https://codereview.chromium.org/1329963002/diff/20001/mojo/devtools/common/RE...
mojo/devtools/common/README.md:72: mojo_run --trace-startup APP_URL [--android]
On 2015/09/07 09:05:49, etiennej wrote:
> On 2015/09/07 08:56:29, ppi wrote:
> > Actually, this should not be placed under ### Debugger. Debugger offers
> > interactive tracing, while this is shell feature. Can we put this under ###
> > Runner?
> 
> Yet, this is related to tracing, and this sub-section is called "Tracing".
Note
> that even the "interactive tracing" needs you to run mojo_run with a
> tracing-specific argument (by reading the documentation, one would think that
> the --debugger flag is only used for tracing).
> 
> Do we really want two "tracing" subsections? Shouldn't we have a "### Tracing"
> section at the same level than Debugger and Runner?

Reworded per offline discussion.

[ppi, 2015-09-07 10:47:56]

lgtm

[etiennej, 2015-09-07 11:05:07]

Committed patchset #3 (id:40001) manually as
94c26b19d3d2580bd41b516b08ddbb1079dfa02b (presubmit successful).