[Startup Tracing] Remove |is_recording_| in devtool tracing_handler

[Startup Tracing] Remove |is_recording_| in devtool tracing_handler

With startup tracing via Telemetry, tracing may be started from places other than devtool (by reading the trace-config file). So devtool should not maintain the state of the tracing system. It can get the information from the TracingController. This requires adding one more function to TracingController's API.

Startup tracing design doc:
https://docs.google.com/document/d/1yRCXhrQ-0rsfUgNHt9T4YdnmJYrXKN6aK56Ozk3kPVc/edit?usp=sharing

BUG=317481, 482098
Committed: https://crrev.com/02348013cae0dcce2b871c6bccfe2f7a034acdea
Cr-Commit-Position: refs/heads/master@{#333574}

[Zhen Wang, 2015-06-08 23:33:14]

zhenw@chromium.org changed reviewers:
+ dsinclair@chromium.org, nednguyen@google.com, yurys@chromium.org

[Zhen Wang, 2015-06-08 23:33:15]

dsinclair@, can you take a look at the tracing part?

yurys@, can you take a look at the devtool part?

Thanks!

[nednguyen, 2015-06-09 02:58:24]

https://codereview.chromium.org/1171813002/diff/1/content/browser/devtools/pr...
File content/browser/devtools/protocol/tracing_handler.h (right):

https://codereview.chromium.org/1171813002/diff/1/content/browser/devtools/pr...
content/browser/devtools/protocol/tracing_handler.h:57: bool IsRecording();
bool IsRecording() const; ?

[Zhen Wang, 2015-06-09 04:01:12]

https://codereview.chromium.org/1171813002/diff/1/content/browser/devtools/pr...
File content/browser/devtools/protocol/tracing_handler.h (right):

https://codereview.chromium.org/1171813002/diff/1/content/browser/devtools/pr...
content/browser/devtools/protocol/tracing_handler.h:57: bool IsRecording();
On 2015/06/09 02:58:23, nednguyen wrote:
> bool IsRecording() const; ?

Done.

[dsinclair, 2015-06-09 14:07:42]

lgtm

[nednguyen, 2015-06-09 15:16:12]

On 2015/06/09 14:07:42, dsinclair wrote:
> lgtm

lgtm

[yurys, 2015-06-09 16:35:18]

lgtm

[Zhen Wang, 2015-06-09 17:00:22]

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

[Zhen Wang, 2015-06-09 17:00:22]

sievers@, can you stamp content/public/browser/tracing_controller.h? Thanks!

[no sievers, 2015-06-09 18:31:04]

On 2015/06/09 17:00:22, Zhen Wang wrote:
> sievers@, can you stamp content/public/browser/tracing_controller.h? Thanks!

lgtm

[Zhen Wang, 2015-06-09 20:33:12]

The CQ bit was checked by zhenw@chromium.org

[commit-bot: I haz the power, 2015-06-09 20:34:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1171813002/20001

[commit-bot: I haz the power, 2015-06-09 21:12:36]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-06-09 21:13:27]

Patchset 2 (id:??) landed as
https://crrev.com/02348013cae0dcce2b871c6bccfe2f7a034acdea
Cr-Commit-Position: refs/heads/master@{#333574}