Revert of Transform ImagePreReader into PreReadFile.

Revert of Transform ImagePreReader into PreReadFile. (patchset #8 id:140001 of https://codereview.chromium.org/1412673006/ )

Reason for revert:
This patch increases cold startup time on XP (crbug.com/551488). Local tests were done on Win8 only, so we didn't catch that regression before submitting the patch.

It's strange that touching pages of a PE file loaded with ::LoadLibraryExW doesn't do the same thing as touching pages of a memory-mapped PE file.

Original issue's description:
> Transform ImagePreReader into PreReadFile.
>
> We can reduce startup time by pre-reading different non-PE files
> (e.g. ChromeDWriteFontCache, GPU cache, resources).
>
> This CL transforms ImagePreReader into PreReadFile, which can
> pre-read any file type.
>
> BUG=547794
>
> Committed: https://crrev.com/031ed3ba5d22e04d7f8ad3641aed82bc9c17f8ae
> Cr-Commit-Position: refs/heads/master@{#357689}

TBR=jochen@chromium.org,grt@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=551488
Committed: https://crrev.com/bc1a48d97b535993c8644acc89fd761da7cd99c2
Cr-Commit-Position: refs/heads/master@{#358049}

[fdoray, 2015-11-05 04:38:48]

Created Revert of Transform ImagePreReader into PreReadFile.

[fdoray, 2015-11-05 05:36:11]

The CQ bit was checked by fdoray@chromium.org

[commit-bot: I haz the power, 2015-11-05 05:36:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1411683010/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1411683010/1

[commit-bot: I haz the power, 2015-11-05 05:36:39]

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

[commit-bot: I haz the power, 2015-11-05 05:36:40]

No L-G-T-M from a valid reviewer yet. Only full committers are accepted.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[fdoray, 2015-11-05 05:37:29]

Description was changed from

==========
Revert of Transform ImagePreReader into PreReadFile. (patchset #8 id:140001 of
https://codereview.chromium.org/1412673006/ )

Reason for revert:
This patch increases cold startup time on XP (crbug.com/551488). Local tests
were done on Win8 only, so we didn't catch that regression before submitting the
patch.

It's strange that touching pages of a PE file loaded with ::LoadLibraryExW
doesn't do the same thing as touching pages of a memory-mapped PE file.

Original issue's description:
> Transform ImagePreReader into PreReadFile.
> 
> We can reduce startup time by pre-reading different non-PE files
> (e.g. ChromeDWriteFontCache, GPU cache, resources).
> 
> This CL transforms ImagePreReader into PreReadFile, which can
> pre-read any file type.
> 
> BUG=547794
> 
> Committed: https://crrev.com/031ed3ba5d22e04d7f8ad3641aed82bc9c17f8ae
> Cr-Commit-Position: refs/heads/master@{#357689}

TBR=jochen@chromium.org,grt@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=547794
==========

to

==========
Revert of Transform ImagePreReader into PreReadFile. (patchset #8 id:140001 of
https://codereview.chromium.org/1412673006/ )

Reason for revert:
This patch increases cold startup time on XP (crbug.com/551488). Local tests
were done on Win8 only, so we didn't catch that regression before submitting the
patch.

It's strange that touching pages of a PE file loaded with ::LoadLibraryExW
doesn't do the same thing as touching pages of a memory-mapped PE file.

Original issue's description:
> Transform ImagePreReader into PreReadFile.
> 
> We can reduce startup time by pre-reading different non-PE files
> (e.g. ChromeDWriteFontCache, GPU cache, resources).
> 
> This CL transforms ImagePreReader into PreReadFile, which can
> pre-read any file type.
> 
> BUG=547794
> 
> Committed: https://crrev.com/031ed3ba5d22e04d7f8ad3641aed82bc9c17f8ae
> Cr-Commit-Position: refs/heads/master@{#357689}

TBR=jochen@chromium.org,grt@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=551488
==========

[fdoray, 2015-11-05 05:43:55]

grt@: Could you review this CL (and maybe check the commit box)? Thanks.

I'll revert the CL first. Then, I'll take more time to understand why this
doesn't work well on XP.

etienneb@ tells me that TouchPagesInRange() might be optimized by the compiler
and that I could use base::Debug::Alias(&dummy); to avoid that. But I don't see
why the new implementation of TouchPagesInRange() would be optimized and not the
old one. The problem might also be due to the fact that before, the image was
loaded by ::LoadModuleEx() and now it's just a memory map.

[grt (UTC plus 2), 2015-11-05 14:11:49]

The CQ bit was checked by grt@chromium.org

[grt (UTC plus 2), 2015-11-05 14:11:50]

lgtm

[commit-bot: I haz the power, 2015-11-05 14:12:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1411683010/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1411683010/1

[commit-bot: I haz the power, 2015-11-05 14:13:21]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-05 14:14:19]

Patchset 1 (id:??) landed as
https://crrev.com/bc1a48d97b535993c8644acc89fd761da7cd99c2
Cr-Commit-Position: refs/heads/master@{#358049}