Prepare for moving nacl_irt_icache definition to the NaCl repository.
Prepare for moving nacl_irt_icache definition to the NaCl repository.

Once nacl_irt_icache has been included in irt.h in the NaCl
repository, Chrome build would fail due to multiple definition error.
This is a change for preparing for the NaCl roll that includes
the NaCl side change.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4033

Review URL: https://codereview.chromium.org/924783003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#316461}

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