Reorganize sandbox operator new, add a comment.
Reorganize sandbox operator new, add a comment.

Now that NT_PAGE is gone, rewrite the function to be single-return and add
a comment pointing out that what the function is doing is incomplete.

No intended behavior change, should fix 2 clang warnings of the form
..\..\sandbox\win\src\sandbox_nt_util.cc(560,3) :  warning(clang): 'operator new' should not return a null pointer unless it is declared 'throw()' or 'noexcept' [-Wnew-returns-null]
  return NULL;
  ^
BUG=82385
R=rvargas@chromium.org

Review URL: https://codereview.chromium.org/556293002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#294246}

PeterWangIntel/chromium-crosswalk,Fireblend/chromium-crosswalk,krieger-od/nwjs_chromium.src,markYoungH/chromium.src,PeterWangIntel/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Fireblend/chromium-crosswalk,Fireblend/chromium-crosswalk,hgl888/chromium-crosswalk,Just-D/chromium-1,hgl888/chromium-crosswalk,jaruba/chromium.src,chuan9/chromium-crosswalk,markYoungH/chromium.src,TheTypoMaster/chromium-crosswalk,Just-D/chromium-1,ltilve/chromium,mohamed--abdel-maksoud/chromium.src,dushu1203/chromium.src,jaruba/chromium.src,TheTypoMaster/chromium-crosswalk,Just-D/chromium-1,hgl888/chromium-crosswalk-efl,Fireblend/chromium-crosswalk,Fireblend/chromium-crosswalk,Jonekee/chromium.src,crosswalk-project/chromium-crosswalk-efl,hgl888/chromium-crosswalk-efl,chuan9/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,markYoungH/chromium.src,PeterWangIntel/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,M4sse/chromium.src,dednal/chromium.src,Pluto-tv/chromium-crosswalk,fujunwei/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,crosswalk-project/chromium-crosswalk-efl,markYoungH/chromium.src,Chilledheart/chromium,chuan9/chromium-crosswalk,dednal/chromium.src,TheTypoMaster/chromium-crosswalk,crosswalk-project/chromium-crosswalk-efl,dushu1203/chromium.src,Fireblend/chromium-crosswalk,krieger-od/nwjs_chromium.src,krieger-od/nwjs_chromium.src,TheTypoMaster/chromium-crosswalk,krieger-od/nwjs_chromium.src,fujunwei/chromium-crosswalk,dushu1203/chromium.src,chuan9/chromium-crosswalk,Pluto-tv/chromium-crosswalk,hgl888/chromium-crosswalk-efl,chuan9/chromium-crosswalk,hgl888/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Fireblend/chromium-crosswalk,Jonekee/chromium.src,PeterWangIntel/chromium-crosswalk,axinging/chromium-crosswalk,hgl888/chromium-crosswalk-efl,Jonekee/chromium.src,M4sse/chromium.src,Chilledheart/chromium,M4sse/chromium.src,hgl888/chromium-crosswalk,Fireblend/chromium-crosswalk,jaruba/chromium.src,hgl888/chromium-crosswalk-efl,TheTypoMaster/chromium-crosswalk,axinging/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Chilledheart/chromium,jaruba/chromium.src,Jonekee/chromium.src,axinging/chromium-crosswalk,krieger-od/nwjs_chromium.src,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,Chilledheart/chromium,markYoungH/chromium.src,Jonekee/chromium.src,ltilve/chromium,hgl888/chromium-crosswalk-efl,Pluto-tv/chromium-crosswalk,krieger-od/nwjs_chromium.src,Chilledheart/chromium,fujunwei/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,krieger-od/nwjs_chromium.src,dushu1203/chromium.src,M4sse/chromium.src,mohamed--abdel-maksoud/chromium.src,ltilve/chromium,hgl888/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,jaruba/chromium.src,chuan9/chromium-crosswalk,dednal/chromium.src,dednal/chromium.src,dushu1203/chromium.src,M4sse/chromium.src,crosswalk-project/chromium-crosswalk-efl,fujunwei/chromium-crosswalk,markYoungH/chromium.src,axinging/chromium-crosswalk,ltilve/chromium,Just-D/chromium-1,TheTypoMaster/chromium-crosswalk,Pluto-tv/chromium-crosswalk,krieger-od/nwjs_chromium.src,markYoungH/chromium.src,axinging/chromium-crosswalk,Jonekee/chromium.src,Just-D/chromium-1,dednal/chromium.src,axinging/chromium-crosswalk,dushu1203/chromium.src,jaruba/chromium.src,dednal/chromium.src,mohamed--abdel-maksoud/chromium.src,Jonekee/chromium.src,jaruba/chromium.src,mohamed--abdel-maksoud/chromium.src,dushu1203/chromium.src,Jonekee/chromium.src,mohamed--abdel-maksoud/chromium.src,dednal/chromium.src,dushu1203/chromium.src,Jonekee/chromium.src,Jonekee/chromium.src,ltilve/chromium,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,krieger-od/nwjs_chromium.src,Jonekee/chromium.src,markYoungH/chromium.src,markYoungH/chromium.src,chuan9/chromium-crosswalk,Chilledheart/chromium,hgl888/chromium-crosswalk,hgl888/chromium-crosswalk,M4sse/chromium.src,dednal/chromium.src,TheTypoMaster/chromium-crosswalk,markYoungH/chromium.src,crosswalk-project/chromium-crosswalk-efl,dushu1203/chromium.src,krieger-od/nwjs_chromium.src,dednal/chromium.src,fujunwei/chromium-crosswalk,ltilve/chromium,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,M4sse/chromium.src,M4sse/chromium.src,hgl888/chromium-crosswalk-efl,dednal/chromium.src,Fireblend/chromium-crosswalk,krieger-od/nwjs_chromium.src,Pluto-tv/chromium-crosswalk,M4sse/chromium.src,fujunwei/chromium-crosswalk,Chilledheart/chromium,crosswalk-project/chromium-crosswalk-efl,mohamed--abdel-maksoud/chromium.src,crosswalk-project/chromium-crosswalk-efl,ltilve/chromium,Just-D/chromium-1,dednal/chromium.src,axinging/chromium-crosswalk,M4sse/chromium.src,jaruba/chromium.src,jaruba/chromium.src,Just-D/chromium-1,markYoungH/chromium.src,Just-D/chromium-1,hgl888/chromium-crosswalk-efl,ltilve/chromium,jaruba/chromium.src,crosswalk-project/chromium-crosswalk-efl,fujunwei/chromium-crosswalk,dushu1203/chromium.src,axin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