Update PDFium to 1b24b69.
Update PDFium to 1b24b69.

The only change since the previous revision is unconditionally using
static_assert in third_party/macros.h.  This gets rid of the old code that used
ALLOW_UNUSED and will ensure there are no conflicts of any kind as I change how
the version of ALLOW_UNUSED in Chromium works.

BUG=81439
TEST=none
TBR=jam

Review URL: https://codereview.chromium.org/654783003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#299412}

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