Moved common cross-project functionality out from SkTraceEvent.h into SkTraceEventCommon.h

Moved common cross-project functionality out from SkTraceEvent.h into SkTraceEventCommon.h

Traditionally, SkTraceEvent.h was manually kept in sync with base/trace_event/trace_event.h, with project-specific parts intermixed, and tended to drift out of sync a lot (mainly in Blink, less so in Skia).

The SkTraceEventCommon.h now has only the cross-project parts, and can be copy-pasted verbatim between projects (it's an identical copy of base/trace_event/trace_event_common.h), meaning SkTraceEvent.h shouldn't go out of sync as it has before.

BUG=skia:

[mtklein mucking around below here]
NOPRESUBMIT=true
CQ_EXCLUDE_TRYBOTS=client.skia.fyi:skia_presubmit-Trybot

Committed: https://skia.googlesource.com/skia/+/dfcba473b0462be3ed4babc07b1d50f4fafaeded

[oystein (OOO til 10th of July), 2015-08-04 20:41:19]

oysteine@chromium.org changed reviewers:
+ reed@google.com

[oystein (OOO til 10th of July), 2015-08-04 20:43:32]

reed: ptal

Note that --bypass-hooks was used and SkTraceEventCommon.h has this presubmit
error:

** Presubmit ERRORS **
The following files have #if or #ifdef before includes:
src/core/SkTraceEventCommon.h


There's an #if check for a macro which'll generate an #error if the file is
included multiple times, instead of normal include guards. The reason for this
is so the file can just be copied verbatim between projects (with different
filenames), so IMO the presubmit violation is justified. Thoughts?

[mtklein_C, 2015-08-05 19:45:54]

On 2015/08/04 20:43:32, Oystein wrote:
> reed: ptal
lgtm

> Note that --bypass-hooks was used and SkTraceEventCommon.h has this presubmit
> error:
> 
> ** Presubmit ERRORS **
> The following files have #if or #ifdef before includes:
> src/core/SkTraceEventCommon.h
> 
> 
> There's an #if check for a macro which'll generate an #error if the file is
> included multiple times, instead of normal include guards. The reason for this
> is so the file can just be copied verbatim between projects (with different
> filenames), so IMO the presubmit violation is justified. Thoughts?

I think this is fine.  The presubmit is here to guard against errors that are
pretty Skia-specific, e.g.

#if SK_SUPPORT_GPU
...
#endif

#include "SkTypes.h"    // Has side effect of determining SK_SUPPORT_GPU.

[mtklein_C, 2015-08-05 19:46:05]

The CQ bit was checked by mtklein@chromium.org

[commit-bot: I haz the power, 2015-08-05 19:46:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1270783002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1270783002/40001

[commit-bot: I haz the power, 2015-08-05 19:47:11]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-08-05 19:47:12]

Try jobs failed on following builders:
  skia_presubmit-Trybot on client.skia.fyi (JOB_FAILED,
http://build.chromium.org/p/client.skia.fyi/builders/skia_presubmit-Trybot/bu...)

[mtklein_C, 2015-08-05 19:48:20]

The CQ bit was checked by mtklein@chromium.org

[commit-bot: I haz the power, 2015-08-05 19:48:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1270783002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1270783002/40001

[mtklein_C, 2015-08-05 19:51:02]

The CQ bit was unchecked by mtklein@chromium.org

[mtklein_C, 2015-08-05 19:51:36]

The CQ bit was checked by mtklein@chromium.org

[commit-bot: I haz the power, 2015-08-05 19:51:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1270783002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1270783002/40001

[commit-bot: I haz the power, 2015-08-05 19:54:43]

Committed patchset #3 (id:40001) as
https://skia.googlesource.com/skia/+/dfcba473b0462be3ed4babc07b1d50f4fafaeded