Fix buffer overflow bug in the brotli encoder.
Fix buffer overflow bug in the brotli encoder.

CyanogenMod/android_external_chromium_org_third_party_brotli_src,seanjensengrey/font-compression-reference,bpsinc-native/src_third_party_brotli_src,seanjensengrey/font-compression-reference,AOSPU/external_chromium_org_third_party_brotli_src,bxchusun/le-huong-van,bxchusun/le-huong-van,bpsinc-native/src_third_party_brotli_src,MIPS/external-chromium_org-third_party-brotli-src,google/woff2,android-ia/platform_external_chromium_org_third_party_brotli_src,rsheeter/woff2,anthrotype/woff2,bxchusun/le-huong-van,Omegaphora/external_chromium_org_third_party_brotli_src,android-ia/platform_external_chromium_org_third_party_brotli_src,AOSPU/external_chromium_org_third_party_brotli_src,MIPS/external-chromium_org-third_party-brotli-src,bxchusun/le-huong-van,seanjensengrey/font-compression-reference,AOSPU/external_chromium_org_third_party_brotli_src,android-ia/platform_external_chromium_org_third_party_brotli_src,Omegaphora/external_chromium_org_third_party_brotli_src,CyanogenMod/android_external_chromium_org_third_party_brotli_src,MIPS/external-chromium_org-third_party-brotli-src,Omegaphora/external_chromium_org_third_party_brotli_src,CyanogenMod/android_external_chromium_org_third_party_brotli_src,bpsinc-native/src_third_party_brotli_src,khaledhosny/woff2