Reland of Precompile more in Blink in Windows for faster compilations

Precompile more in Blink in Windows for faster compilations
 
One reason Blink is slow to compile is that there is a lot of code
included in every compilation unit since everything depends on either
LayoutObject.h or Document.h and those in turn include huge portions
of the rest of Blink.

By precompiling LayoutObject.h and Document.h the compilation of core and
modules in Blink can be 4 times faster (4 minutes instead of
19 minutes on my computer).

The downside is that it will introduce Document.h and LayoutObject.h
also in compilation units that didn't expect it, for instance
XPathGrammer.y that suddenly will have both blink::Path and
blink::XPath::Path in scope (and blink::Filter / blink::XPath::Filter)

Note that distributed compilation system disables precompiled headers
globally so this will *not* make trybots faster.

This is a new attempt at this change after bug 511945 scared us into
reverting it. We still do not know the exact cause of 511945 but we
are making another attempt with this.

BUG=495697
R=thakis@chromium.org,sigbjornf@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=199168

[Daniel Bratell, 2015-07-17 14:04:04]

Created Reland of Precompile more in Blink in Windows for faster compilations

[sof, 2015-07-19 17:07:53]

lgtm - makes good sense to reland to try determine where that bot ailment came
from.

[Nico, 2015-07-19 17:16:23]

is there a bug somewhere that summarizes what the failure looked like? it went
away after the revert, right?

[sof, 2015-07-19 18:11:24]

On 2015/07/19 17:16:23, Nico wrote:
> is there a bug somewhere that summarizes what the failure looked like? it went
> away after the revert, right?

As remarked in 

 https://codereview.chromium.org/1167523007/#msg46

it went away before the revert was in scope. A clobbering build?

[Nico, 2015-07-19 18:25:25]

lgtm

[Nico, 2015-07-19 18:26:05]

(I do wish that there had been left more details on a bug somewhere: Link to bot
that broke, error message, link to first build that no longer had the breakage,
etc)

[Daniel Bratell, 2015-07-20 12:09:05]

Thanks!

I've opened https://code.google.com/p/chromium/issues/detail?id=511945 with lots
of links to builds and explanation of various events and errors.

[Daniel Bratell, 2015-07-20 12:09:09]

The CQ bit was checked by bratell@opera.com

[commit-bot: I haz the power, 2015-07-20 12:09:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1227953008/1

[commit-bot: I haz the power, 2015-07-20 13:41:21]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=199168

[Daniel Bratell, 2015-07-24 09:47:20]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1259563002/ by bratell@opera.com.

The reason for reverting is: A chromium build bot broke with bad headers again.
(see bug)

The pch file does not seem to be recompiled when it should be.

BUG=511945.