Revert of Replace system IO calls in chromecast/crash with Chrome utilities.

Revert of Replace system IO calls in chromecast/crash with Chrome utilities. (patchset #9 id:160001 of https://codereview.chromium.org/1227963002/)

Reason for revert:
Breaks CastCrashReporterClientTest.EndToEndTestOnIORestrictedThread:

https://build.chromium.org/p/chromium.linux/builders/Cast%20Linux/builds/2709

Original issue's description:
> Replace system IO calls in chromecast/crash with Chrome utilities.
>
> System IO calls had been used to avoid thread IO restrictions in the
> crash handler. This change replaces each of these calls with the more
> platform-independent, stable Chrome IO utilities from ::base. Thread
> restrictions are disabled in crash_util.cc.
>
> BUG= b/22329428
>
> Committed: https://crrev.com/4927df40d0342522fc268f884835b43f9004549e
> Cr-Commit-Position: refs/heads/master@{#339161}

TBR=wzhong@chromium.org,bcf@google.com,gunsch@chromium.org,gfhuang@chromium.org,slan@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG= b/22329428

Committed: https://crrev.com/4306386450441c312f0e94af12074ae1534b4117
Cr-Commit-Position: refs/heads/master@{#339183}

[dcaiafa, 2015-07-17 00:06:56]

Created Revert of Replace system IO calls in chromecast/crash with Chrome
utilities.

[commit-bot: I haz the power, 2015-07-17 00:07:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1239083005/1

[commit-bot: I haz the power, 2015-07-17 00:10:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-17 00:11:36]

Patchset 1 (id:??) landed as
https://crrev.com/4306386450441c312f0e94af12074ae1534b4117
Cr-Commit-Position: refs/heads/master@{#339183}

[slan, 2015-07-17 16:37:36]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1240843003/ by slan@chromium.org.

The reason for reverting is: The offending test case shall be guarded with
ENABLE_THREAD_RESTRICTIONS..