Use precompiled headers on Windows only when a flag is set.

Use precompiled headers on Windows only when a flag is set.

I would have preferred if precompiled headers could be enabled by
default. The motivation for this change is primarily that Visual
Studio does the wrong thing on preprocessor flag changes - instead of
rebuilding precompiled headers, it errors out on any file that uses
them, saying that the precompiled header was built with different
flags! This causes a world of hurt on our infrastructure stuff,
particularly on trybots as they may be jumping back and forth between
revisions before and after a flag change.

Prior to this change, only Debug builds used precompiled headers and
Release builds did not. The reason Release builds did not was that
official builds were running out of memory with precompiled headers
enabled. The distinction of Debug vs. Release is no longer necessary
after the flag is added, so removing that extra bit of complexity from
the .gyp files.

BUG=none
TEST=it builds


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=102839

[M-A Ruel, 2011-09-26 16:04:27]

Mark, what do you think?

http://codereview.chromium.org/8041022/diff/5/build/common.gypi
File build/common.gypi (right):

http://codereview.chromium.org/8041022/diff/5/build/common.gypi#newcode221
build/common.gypi:221: 'win_use_pch%': 0,
I find it sad that chromium_mac_pch and win_use_pch. IMHO there is no need to
specify the OS there, it's unambiguously a flag to enable it if possible.

[Jói, 2011-09-26 16:06:49]

True, but seeing as they have different default values I'm not sure
whether we can combine them for now?

On Mon, Sep 26, 2011 at 4:04 PM,  <maruel@chromium.org> wrote:
> Mark, what do you think?
>
>
> http://codereview.chromium.org/8041022/diff/5/build/common.gypi
> File build/common.gypi (right):
>
> http://codereview.chromium.org/8041022/diff/5/build/common.gypi#newcode221
> build/common.gypi:221: 'win_use_pch%': 0,
> I find it sad that chromium_mac_pch and win_use_pch. IMHO there is no
> need to specify the OS there, it's unambiguously a flag to enable it if
> possible.
>
> http://codereview.chromium.org/8041022/
>

[M-A Ruel, 2011-09-26 16:09:05]

On 2011/09/26 16:06:49, Jói wrote:
> True, but seeing as they have different default values I'm not sure
> whether we can combine them for now?

Right, but what about using a similar name? e.g. chromium_win_pch?

[Mark Mentovai, 2011-09-26 16:10:59]

http://codereview.chromium.org/8041022/diff/5/build/common.gypi
File build/common.gypi (right):

http://codereview.chromium.org/8041022/diff/5/build/common.gypi#newcode221
build/common.gypi:221: 'win_use_pch%': 0,
Marc-Antoine Ruel wrote:
> I find it sad that chromium_mac_pch and win_use_pch. IMHO there is no need to
> specify the OS there, it's unambiguously a flag to enable it if possible.

The Mac buildbots may have this set in unexpected places, like in
~/.gyp/include.gypi. If you change the name used on the Mac, you’ll need to
track down these locations and fix them.

[Jói, 2011-09-26 16:15:49]

> Right, but what about using a similar name? e.g. chromium_win_pch?

No problem to change the name.  Would you like me to?

On Mon, Sep 26, 2011 at 4:09 PM,  <maruel@chromium.org> wrote:
> On 2011/09/26 16:06:49, Jói wrote:
>>
>> True, but seeing as they have different default values I'm not sure
>> whether we can combine them for now?
>
> Right, but what about using a similar name? e.g. chromium_win_pch?
>
> http://codereview.chromium.org/8041022/
>

[M-A Ruel, 2011-09-26 16:17:02]

On 2011/09/26 16:15:49, Jói wrote:
> > Right, but what about using a similar name? e.g. chromium_win_pch?
> 
> No problem to change the name.  Would you like me to?

yep.

[Jói, 2011-09-26 16:21:19]

Done.

On Mon, Sep 26, 2011 at 4:17 PM,  <maruel@chromium.org> wrote:
> On 2011/09/26 16:15:49, Jói wrote:
>>
>> > Right, but what about using a similar name? e.g. chromium_win_pch?
>
>> No problem to change the name.  Would you like me to?
>
> yep.
>
>
> http://codereview.chromium.org/8041022/
>

[M-A Ruel, 2011-09-26 16:23:03]

lgtm

[M-A Ruel, 2011-09-26 20:21:20]

On 2011/09/26 16:23:03, Marc-Antoine Ruel wrote:
> lgtm

Please commit asap.

[commit-bot: I haz the power, 2011-09-26 20:59:23]

CQ is trying tha patch. Follow status at
https://chromium-status.appspot.com/cq/joi@chromium.org/8041022/2003

[commit-bot: I haz the power, 2011-09-27 00:15:19]

Change committed as 102839

[Jói, 2011-09-27 10:47:40]

Sorry, wasn't able to be around on IRC last night so was going to
commit it this morning.  Thanks for doing it for me.

On Mon, Sep 26, 2011 at 8:21 PM,  <maruel@chromium.org> wrote:
> On 2011/09/26 16:23:03, Marc-Antoine Ruel wrote:
>>
>> lgtm
>
> Please commit asap.
>
> http://codereview.chromium.org/8041022/
>