WIP: Migrate Wiki content over to src/docs

docs/updating_clang_format_binaries.md

+Instructions on how to update the [clang-format binaries](ClangFormat.md) that come with a checkout of Chromium.
+
+<h2>Prerequisites</h2>
+
+You'll need a Windows machine, a Linux machine, and a Mac; all capable of building clang-format. You'll also need permissions to upload to the appropriate google storage bucket. Chromium infrastructure team members have this, and others can be granted the permission based on need. Talk to ncarter or hinoka about getting access.
+
+<h2>Pick a head svn revision</h2>
+
+Consult http://llvm.org/svn/llvm-project/ for the current head revision. This will be the CLANG\_REV you'll use later to check out each platform to a consistent state.
+
+<h2>Build a release-mode clang-format on each platform</h2>
+
+Follow the the official instructions here: http://clang.llvm.org/get_started.html.
+
+Windows step-by-step:
+```
+[double check you have the tools you need]
+where cmake.exe  # You need to install this.
+where svn.exe  # Maybe fix with: set PATH=%PATH%;D:\src\depot_tools\svn_bin
+"c:\Program Files (x86)\Microsoft Visual Studio 12.0\vc\vcvarsall.bat" amd64_x86
+
+
+set CLANG_REV=198831  # You must change this value (see above)
+
+[from a clean directory, check out and build]
+rmdir /S /Q llvm
+rmdir /S /Q llvm-build
+mkdir llvm
+mkdir llvm-build
+svn co http://llvm.org/svn/llvm-project/llvm/trunk@%CLANG_REV% llvm
+cd llvm\tools
+svn co http://llvm.org/svn/llvm-project/cfe/trunk@%CLANG_REV% clang
+cd ..\..\llvm-build
+set CC=cl
+set CXX=cl
+cmake -G Ninja ..\llvm -DCMAKE_BUILD_TYPE=Release -DLLVM_USE_CRT_RELEASE=MT -DLLVM_ENABLE_ASSERTIONS=NO -DLLVM_ENABLE_THREADS=NO -DPYTHON_EXECUTABLE=d:\src\depot_tools\python276_bin\python.exe
+ninja clang-format
+bin\clang-format.exe --version
+```
+
+Mac & Linux step-by-step:
+```
+# Check out.
+export CLANG_REV=198831   # You must change this value (see above)
+rm -rf llvm
+rm -rf llvm-build
+mkdir llvm
+mkdir llvm-build
+svn co http://llvm.org/svn/llvm-project/llvm/trunk@$CLANG_REV llvm
+cd llvm/tools
+svn co http://llvm.org/svn/llvm-project/cfe/trunk@$CLANG_REV clang
+cd ../../llvm-build
+
+# Option 1: with cmake
+  MACOSX_DEPLOYMENT_TARGET=10.9 cmake -G Ninja  -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_ASSERTIONS=NO -DLLVM_ENABLE_THREADS=NO ../llvm/
+  time caffeinate ninja clang-format 
+  strip bin/clang-format
+
+  # (On Linux, to build with clang, which produces smaller binaries, add this to your cmake invocation.
+  # On Mac, the system compiler is already clang so it's not needed there.)
+  -DCMAKE_C_COMPILER=$PWD/../chrome/src/third_party/llvm-build/Release+Asserts/bin/clang -DCMAKE_CXX_COMPILER=$PWD/../chrome/src/third_party/llvm-build/Release+Asserts/bin/clang++ 
+```
+Platform specific notes:
+  * Windows: Visual Studio 2013 only.
+  * Linux: so far (as of January 2014) we've just included a 64-bit binary. It's important to disable threading, else clang-format will depend on libatomic.so.1 which doesn't exist on Precise.
+  * Mac: Remember to set `MACOSX_DEPLOYMENT_TARGET` when building! If you get configure warnings, you may need to install XCode 5 and avoid a goma environment.
+
+<h2>Upload each binary to google storage</h2>
+
+Copy the binaries into your chromium checkout (under `src/buildtools/(win|linux64|mac)/clang-format(.exe?)`).
+For each binary, you'll need to run upload\_to\_google\_storage.py according to the instructions in [README.txt](https://code.google.com/p/chromium/codesearch#chromium/src/buildtools/clang_format/README.txt). This will upload the binary into a publicly accessible google storage bucket, and update `.sha1` file in your Chrome checkout. You'll check in the `.sha1` file (but NOT the clang-format binary) into source control. In order to be able to upload, you'll need write permission to the bucket -- see the prerequisites.
+
+<h2>Copy the helper scripts and update README.chromium</h2>
+
+There are some auxiliary scripts that ought to be kept updated in lockstep with the clang-format binary. These get copied into third\_party/clang\_format/scripts in your Chromium checkout.
+
+The `README.chromium` file ought to be updated with version and date info.
+
+<h2>Upload a CL according to the following template</h2>
+
+```
+Update clang-format binaries and scripts for all platforms.
+
+I followed these instructions:
+https://code.google.com/p/chromium/wiki/UpdatingClangFormatBinaries
+
+The binaries were built at clang revision ####### on ####DATETIME####.
+
+BUG=
+```
+
+The change should <b>always</b> include new `.sha1` files for each platform (we want to keep these in lockstep), should <b>never</b> include `clang-format` binaries directly. The change should <b>always</b> update `README.chromium`
+
+clang-format binaries should weigh in at 1.5MB or less. Watch out for size regressions.