Tracing: do not pass entire trace content in TraceDataEndpoint::ReceiveTraceFinalContents

Tracing: do not pass entire trace content in TraceDataEndpoint::ReceiveTraceFinalContents

- do not collect the entire trace in intermediate classes of trace data
    pipeline;
- only pass trace data in chunks, don't pass complete trace
    in ReceiveTraceFinalContents;
- rename StringTraceDataSink to JSONTraceDataSink as it is now mostly
    concerned with packaging trace pieces into JSON, and producing a string
    is handled by an endpoint.

Committed: https://crrev.com/647dfe6fe658b5fc62a99854dc1e0d9308604f09
Cr-Commit-Position: refs/heads/master@{#405668}

[caseq, 2016-07-13 22:35:56]

Patchset #1 (id:1) has been deleted

[caseq, 2016-07-13 23:59:34]

caseq@chromium.org changed reviewers:
+ oysteine@chromium.org

[caseq, 2016-07-13 23:59:35]

Hey Oysteine,

thanks a lot for reviewing the first batch! Here's a bit more :-)

[oystein (OOO til 10th of July), 2016-07-14 22:04:33]

lgtm w/nits, great!

https://codereview.chromium.org/2152603002/diff/20001/content/browser/tracing...
File content/browser/tracing/tracing_controller_impl_data_sinks.cc (right):

https://codereview.chromium.org/2152603002/diff/20001/content/browser/tracing...
content/browser/tracing/tracing_controller_impl_data_sinks.cc:34:
trace_.str("");
nit: Should technically also do trace_.clear() in addition to this, to clear
ostringstream flags.

https://codereview.chromium.org/2152603002/diff/20001/content/browser/tracing...
content/browser/tracing/tracing_controller_impl_data_sinks.cc:184: bool
first_chunk_;
nit: has_received_first_chunk_ (and inverted checks) may be clearer.

[caseq, 2016-07-15 00:31:58]

Patchset #2 (id:40001) has been deleted

[caseq, 2016-07-15 00:45:30]

On 2016/07/14 22:04:33, oystein wrote:
> lgtm w/nits, great!
> 
>
https://codereview.chromium.org/2152603002/diff/20001/content/browser/tracing...
> File content/browser/tracing/tracing_controller_impl_data_sinks.cc (right):
> 
>
https://codereview.chromium.org/2152603002/diff/20001/content/browser/tracing...
> content/browser/tracing/tracing_controller_impl_data_sinks.cc:34:
> trace_.str("");
> nit: Should technically also do trace_.clear() in addition to this, to clear
> ostringstream flags.

Done, though this brings up a question of whether we consider the sinks
reusable. Many aren't now (e.g. in case of files this would result in the same
file being overwritten, while compressed string sink would fail on reuse because
we never reset already_tried_open_. I'd leave them this way, though I guess we
need some asserts there.

>
https://codereview.chromium.org/2152603002/diff/20001/content/browser/tracing...
> content/browser/tracing/tracing_controller_impl_data_sinks.cc:184: bool
> first_chunk_;
> nit: has_received_first_chunk_ (and inverted checks) may be clearer.

Done.

[caseq, 2016-07-15 00:46:12]

The CQ bit was checked by caseq@chromium.org

[caseq, 2016-07-15 00:46:13]

The patchset sent to the CQ was uploaded after l-g-t-m from
oysteine@chromium.org
Link to the patchset: https://codereview.chromium.org/2152603002/#ps60001
(title: "review comments addressed")

[commit-bot: I haz the power, 2016-07-15 00:46:57]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-15 01:32:52]

Committed patchset #2 (id:60001)

[commit-bot: I haz the power, 2016-07-15 01:34:54]

Description was changed from

==========
Tracing: do not pass entire trace content in
TraceDataEndpoint::ReceiveTraceFinalContents

- do not collect the entire trace in intermediate classes of trace data
    pipeline;
- only pass trace data in chunks, don't pass complete trace
    in ReceiveTraceFinalContents;
- rename StringTraceDataSink to JSONTraceDataSink as it is now mostly
    concerned with packaging trace pieces into JSON, and producing a string
    is handled by an endpoint.
==========

to

==========
Tracing: do not pass entire trace content in
TraceDataEndpoint::ReceiveTraceFinalContents

- do not collect the entire trace in intermediate classes of trace data
    pipeline;
- only pass trace data in chunks, don't pass complete trace
    in ReceiveTraceFinalContents;
- rename StringTraceDataSink to JSONTraceDataSink as it is now mostly
    concerned with packaging trace pieces into JSON, and producing a string
    is handled by an endpoint.

Committed: https://crrev.com/647dfe6fe658b5fc62a99854dc1e0d9308604f09
Cr-Commit-Position: refs/heads/master@{#405668}
==========

[commit-bot: I haz the power, 2016-07-15 01:34:55]

Patchset 2 (id:??) landed as
https://crrev.com/647dfe6fe658b5fc62a99854dc1e0d9308604f09
Cr-Commit-Position: refs/heads/master@{#405668}