Revert of More regular Platform implementations in unit tests.

Revert of More regular Platform implementations in unit tests. (patchset #12 id:220001 of https://codereview.chromium.org/1456873003/ )

Reason for revert:
Compile break on Win x64 Builder (dbg):

FAILED: ninja -t msvc -e environment.x64 -- C:\b\build\goma/gomacc "C:\b\depot_tools\win_toolchain\vs2013_files\VC\bin\amd64\cl.exe" /nologo /showIncludes /FC @obj\third_party\WebKit\Source\platform\testing\blink_platform_test_support.TestingPlatformSupport.obj.rsp /c ..\..\third_party\WebKit\Source\platform\testing\TestingPlatformSupport.cpp /Foobj\third_party\WebKit\Source\platform\testing\blink_platform_test_support.TestingPlatformSupport.obj /Fdobj\third_party\WebKit\Source\platform\blink_platform_test_support.cc.pdb
c:\b\build\slave\win_x64_builder__dbg_\build\src\third_party\webkit\source\platform\heap\heappage.h(188) : error C2220: warning treated as error - no 'object' file generated
c:\b\build\slave\win_x64_builder__dbg_\build\src\third_party\webkit\source\platform\heap\heappage.h(188) : warning C4267: '=' : conversion from 'size_t' to 'uint32_t', possible loss of data
c:\b\build\slave\win_x64_builder__dbg_\build\src\third_party\webkit\source\platform\heap\heappage.h(202) : warning C4267: '=' : conversion from 'size_t' to 'uint32_t', possible loss of data
c:\b\build\slave\win_x64_builder__dbg_\build\src\third_party\webkit\source\wtf\vector.h(654) : warning C4267: '=' : conversion from 'size_t' to 'unsigned int', possible loss of data
        c:\b\build\slave\win_x64_builder__dbg_\build\src\third_party\webkit\source\wtf\vector.h(644) : while compiling class template member function 'WTF::Vector<char,0x00,WTF::PartitionAllocator>::Vector(size_t)'
        c:\b\build\slave\win_x64_builder__dbg_\build\src\third_party\webkit\source\platform\testing\testingplatformsupport.cpp(38) : see reference to function template instantiation 'WTF::Vector<char,0x00,WTF::PartitionAllocator>::Vector(size_t)' being compiled
        c:\b\build\slave\win_x64_builder__dbg_\build\src\third_party\webkit\source\platform\testing\testingplatformsupport.h(55) : see reference to class template instantiation 'WTF::Vector<char,0x00,WTF::PartitionAllocator>' being compiled

Original issue's description:
> More regular Platform implementations in unit tests.
>
> R=haraken,jbroman
> BUG=
>
> Committed: https://crrev.com/3e197be3a60195ac2267f3293084fa36c5706503
> Cr-Commit-Position: refs/heads/master@{#360583}

TBR=jbroman@chromium.org,haraken@chromium.org,tkent@chromium.org,sigbjornf@opera.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Committed: https://crrev.com/a1f9ec427ed75d7c0745d38f94cb462d08ae184e
Cr-Commit-Position: refs/heads/master@{#360584}

[grt (UTC plus 2), 2015-11-19 15:34:13]

Created Revert of More regular Platform implementations in unit tests.

[commit-bot: I haz the power, 2015-11-19 15:34:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1464493002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1464493002/1

[commit-bot: I haz the power, 2015-11-19 15:36:15]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-19 15:37:28]

Patchset 1 (id:??) landed as
https://crrev.com/a1f9ec427ed75d7c0745d38f94cb462d08ae184e
Cr-Commit-Position: refs/heads/master@{#360584}

[sof, 2015-11-19 15:44:25]

lgtm, thanks much for the revert. Odd error not caught by CQ bots.

[sof, 2015-11-19 16:07:21]

On 2015/11/19 15:44:25, sof wrote:
> lgtm, thanks much for the revert. Odd error not caught by CQ bots.

Latent issue surfacing here afaict; addressing via
https://codereview.chromium.org/1459933002/

[haraken, 2015-11-19 23:16:57]

LGTM