GitLab

This pulls in the following Native Client changes:

r13227: (dyen) Standardized method to define extra substitution paths in toolchain_main.
r13228: (dschuff) Do not build PNaCl host toolchain with build.sh
r13229: (sbc) Add downloaded gn binaries to .gitignore
r13230: (dschuff) Remove cloud-bucket flag from PNaCl package_version update script
r13231: (bradnelson) Download spec2k to out instead of assuming it will be installed on the bots.
r13232: (dschuff) Make build.sh use the repository directories from toolchain/build
r13233: (jvoung) Download the spec harness on the rest of the spec bots.
r13234: (sehr) Disable conflicting sysroot= in chromium arm build
r13235: (kschimpf) PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS
r13236: (kschimpf) PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS
r13237: (dschuff) Update revision for PNaCl r13222->r13228
r13238: (kschimpf) PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS
r13239: (mcgrathr) toolchain_build: Update gcc revision (4.8.3 release)
r13240: (mseaborn) PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS
r13241: (noelallen) Add OWNERS per-file *.gn for noeallen and bradnelson
r13242: (noelallen) Untar raw toolchain and build cooked toolchain.
r13243: (mcgrathr) Update nacl_arm_newlib toolchain
r13244: (dyen) Toolchain build now displays solutions when an invalid repo is found.
r13245: (mseaborn) PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS

BUG=none
TEST=browser_tests and nacl_integration

Review URL: https://codereview.chromium.org/300033004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@272980 0039d316-1c4b-4281-b951-d872f2087c98