Revert of Add DCHECKS() for current thread in ChildProcessLauncher (patchset #4 id:60001 of https://codereview.chromium.org/1002853003/)
Revert of Add DCHECKS() for current thread in ChildProcessLauncher (patchset #4 id:60001 of https://codereview.chromium.org/1002853003/)

Reason for revert:
Broke linux_blink_rel try bots.

http://build.chromium.org/p/tryserver.blink/builders/linux_blink_rel/builds/53723/steps/webkit_tests%20%28with%20patch%29/logs/stdio
> [20222:20222:0322/165944:1212144529:FATAL:child_process_launcher.cc(508)] Check failed: ::content::BrowserThread::CurrentlyOn(client_thread_id_). Must be called on Chrome_UIThread; actually called on CrBrowserMain.

Original issue's description:
> Add DCHECKS() for current thread in ChildProcessLauncher
>
> And rename some functions to indicate when they don't run
> on the default (client) thread.
>
> This avoids misuse and makes it more obvious what threads we are on
> given that this involves multiple threads (launcher thread, and
> different client threads for renderers and other children - former
> calls from UI thread, the latter from IO thread -
> plus there are some Android quirks).
>
> BUG=469248
>
> Committed: https://crrev.com/8efc3b5a5e7b24ffeed0e5576a725b77868eb9ab
> Cr-Commit-Position: refs/heads/master@{#321648}

TBR=rvargas@chromium.org,sievers@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=469248

Review URL: https://codereview.chromium.org/1025923002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#321723}

TheTypoMaster/chromium-crosswalk,Chilledheart/chromium,fujunwei/chromium-crosswalk,hgl888/chromium-crosswalk,Pluto-tv/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Pluto-tv/chromium-crosswalk,fujunwei/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,chuan9/chromium-crosswalk,chuan9/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,ltilve/chromium,PeterWangIntel/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,Fireblend/chromium-crosswalk,fujunwei/chromium-crosswalk,hgl888/chromium-crosswalk,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,fujunwei/chromium-crosswalk,Just-D/chromium-1,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,chuan9/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,ltilve/chromium,Chilledheart/chromium,TheTypoMaster/chromium-crosswalk,Chilledheart/chromium,hgl888/chromium-crosswalk,hgl888/chromium-crosswalk,Pluto-tv/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Fireblend/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,Chilledheart/chromium,Pluto-tv/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Chilledheart/chromium,TheTypoMaster/chromium-crosswalk,Just-D/chromium-1,chuan9/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Pluto-tv/chromium-crosswalk,ltilve/chromium,ltilve/chromium,hgl888/chromium-crosswalk,fujunwei/chromium-crosswalk,ltilve/chromium,Chilledheart/chromium,hgl888/chromium-crosswalk,fujunwei/chromium-crosswalk,Just-D/chromium-1,Chilledheart/chromium,chuan9/chromium-crosswalk,Chilledheart/chromium,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,chuan9/chromium-crosswalk,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,hgl888/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,axinging/chromium-crosswalk,fujunwei/chromium-crosswalk,Just-D/chromium-1,axinging/chromium-crosswalk,ltilve/chromium,ltilve/chromium,Chilledheart/chromium,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Fireblend/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Just-D/chromium-1,Fireblend/chromium-crosswalk,ltilve/chromium,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,chuan9/chromium-crosswalk,Fireblend/chromium-crosswalk,Fireblend/chromium-crosswalk,ltilve/chromium,Fireblend/chromium-crosswalk,chuan9/chromium-crosswalk,Fireblend/chromium-crosswalk,Just-D/chromium-1,Fireblend/chromium-crosswalk