Disabled EnableStartupTracing for Renderer process.

Disabled EnableStartupTracing for Renderer process.

After discussion with zhenw@ seems like intention was not to call this for Renderer as there is alternate way (When IPC is setup) for tracing. On Windows this was getting called through renderer as well.

This function came to notice when applying AppContainer token on Windows 10 where SHGetFolderPath takes different path and crashes. EnableStartupTracing ends up calling SHGetFolderPath(DIR_HOME).

R=zhenw@chromium.org,jam@chromium.org,jschuh@chromium.org,cpu@chromium.org
BUG=506017
Committed: https://crrev.com/bf352277bc6d2c9a86c35020a78ac6f80e5083bb
Cr-Commit-Position: refs/heads/master@{#338917}

[Zhen Wang, 2015-07-01 00:41:43]

zhenw@chromium.org changed reviewers:
+ dsinclair@chromium.org

[Zhen Wang, 2015-07-01 00:41:43]

+dsinclair for tracing owner.

https://codereview.chromium.org/1212893009/diff/1/content/app/content_main_ru...
File content/app/content_main_runner.cc (right):

https://codereview.chromium.org/1212893009/diff/1/content/app/content_main_ru...
content/app/content_main_runner.cc:638: // will stop tracing on demand later.
Can you add some comment here to explain why it is ok to skip renderer process
here? Something like:

When ChildTraceMessageFilter is added, Renderer process will start tracing
automatically if tracing is already started in Browser process.

[cpu_(ooo_6.6-7.5), 2015-07-01 17:52:24]

lgtm

note that as we put other process types into appcontainers we need to keep
fixing this condition.

[Will Harris, 2015-07-01 18:09:55]

On 2015/07/01 17:52:24, cpu wrote:
> lgtm
> 
> note that as we put other process types into appcontainers we need to keep
> fixing this condition.

Can this instead just be called from Browser or does this have to be all
processes except zygote and renderer? If so can it be moved into
browsermainparts?

[Zhen Wang, 2015-07-01 18:19:47]

On 2015/07/01 18:09:55, Will Harris wrote:
> Can this instead just be called from Browser or does this have to be all
> processes except zygote and renderer? If so can it be moved into
> browsermainparts?

This should be called as early as possible for all processes, e.g., including
GPU process. It cannot be called for zygote and renderer because:
- zygote process does not allow multi-thread.
- renderer process on Win10 has stricker rules on accessing the file system now.

Therefore, for renderers, we use other ways to start tracing.

[jam, 2015-07-08 19:30:51]

cpu lgtm'd, do you still need me?

[Shrikant Kelkar, 2015-07-15 19:44:00]

The CQ bit was checked by shrikant@chromium.org

[commit-bot: I haz the power, 2015-07-15 19:45:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1212893009/1

[commit-bot: I haz the power, 2015-07-15 21:24:02]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-15 21:25:58]

Patchset 1 (id:??) landed as
https://crrev.com/bf352277bc6d2c9a86c35020a78ac6f80e5083bb
Cr-Commit-Position: refs/heads/master@{#338917}