Use command line to signal whether a child process was passed V8 snapshot files via file descriptor

Use command line to signal whether a child process was passed V8 snapshot files via file descriptor

BUG=466917
Committed: https://crrev.com/537203ed6059030168776d50fefdd6c9a7bf677a
Cr-Commit-Position: refs/heads/master@{#324600}

[rmcilroy, 2015-04-09 14:32:41]

rmcilroy@chromium.org changed reviewers:
+ gunsch@chromium.org, jamescook@chromium.org, jochen@chromium.org

[rmcilroy, 2015-04-09 14:32:41]

gunsch@chromium.org: Please review changes in chromecast
jamescook@chromium.org: Please review changes in ash / extensions
jochen@chromium.org: Please review changes in content / chrome

PTAL, thanks!

vitalybuka@ FYI - this is a more permanent fix for crbug.com/466917
erikcorry@ FYI - this should help you with the snapshot generation on-demand.

[rmcilroy, 2015-04-09 14:39:07]

The CQ bit was checked by rmcilroy@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-04-09 14:40:22]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1071173002/1

[commit-bot: I haz the power, 2015-04-09 14:49:43]

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

[commit-bot: I haz the power, 2015-04-09 14:49:44]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[jochen (gone - plz use gerrit), 2015-04-09 15:00:19]

lgtm once it compiles

[gunsch, 2015-04-09 15:43:45]

On 2015/04/09 15:00:19, jochen wrote:
> lgtm once it compiles

lgtm

can you also humor me and:

git cl try -m tryserver.chromium.linux -b cast_shell_linux -b cast_shell_android

[James Cook, 2015-04-09 16:27:08]

LGTM with a drive-by comment on the switches

https://codereview.chromium.org/1071173002/diff/1/content/public/common/conte...
File content/public/common/content_switches.cc (right):

https://codereview.chromium.org/1071173002/diff/1/content/public/common/conte...
content/public/common/content_switches.cc:406: const char
kV8SnapshotPassedByFD[] = "v8-snapshot-passed-by-fd";
Is it ever valid to pass just one of these files and not the other?  If they
always go together consider just using a single switch -- it'll make it less
likely for someone to miss one, or pass the same one twice.

[rmcilroy, 2015-04-09 22:15:00]

https://codereview.chromium.org/1071173002/diff/1/content/public/common/conte...
File content/public/common/content_switches.cc (right):

https://codereview.chromium.org/1071173002/diff/1/content/public/common/conte...
content/public/common/content_switches.cc:406: const char
kV8SnapshotPassedByFD[] = "v8-snapshot-passed-by-fd";
On 2015/04/09 16:27:08, James Cook wrote:
> Is it ever valid to pass just one of these files and not the other?  If they
> always go together consider just using a single switch -- it'll make it less
> likely for someone to miss one, or pass the same one twice.

Currently we will always pass both files, however there is a change in-progress
to generate the snapshot file on-demand, which would mean we would pass the
natives file, but not the snapshot file - this is the reason I made this two
separate switches.

[rmcilroy, 2015-04-09 22:20:14]

The CQ bit was checked by rmcilroy@chromium.org to run a CQ dry run

[rmcilroy, 2015-04-09 22:20:14]

The patchset sent to the CQ was uploaded after l-g-t-m from
jamescook@chromium.org, jochen@chromium.org, gunsch@chromium.org
Link to the patchset: https://codereview.chromium.org/1071173002/#ps20001
(title: "Fix compile error")

[commit-bot: I haz the power, 2015-04-09 22:21:18]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1071173002/20001

[James Cook, 2015-04-09 22:27:15]

OK, that makes sense. Still LGTM

[commit-bot: I haz the power, 2015-04-10 01:05:22]

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

[commit-bot: I haz the power, 2015-04-10 01:05:24]

This issue passed the CQ dry run.

[rmcilroy, 2015-04-10 07:51:11]

The CQ bit was checked by rmcilroy@chromium.org

[commit-bot: I haz the power, 2015-04-10 07:51:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1071173002/20001

[commit-bot: I haz the power, 2015-04-10 07:52:31]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-10 07:53:28]

Patchset 2 (id:??) landed as
https://crrev.com/537203ed6059030168776d50fefdd6c9a7bf677a
Cr-Commit-Position: refs/heads/master@{#324600}