use system libhunspell-dev
use system vpx (should be in sync now)

remove third_party/npapi

disable extensions?

webrtc seems to get built regardles of enable_webrtc=0?

remove sync

don't support breakpad (remove a lot of stuff from breakpad/src/third_party)

remove chrome_elf?
remove cloud_print (not available in printers anyway)?

disable bluetooth

remove third_party/WebKit/Source/wtf/unicode?

remove third_party/khronos (need to handle their changes, including gl2chromium.h from gl2.h)
remove third_party/mesa

remove third_party/liblouis (link liblouis2-dev)?
remove third_party/swig (use swig package)?
remove third_party/ply (use python-ply)?
remove third_party/lzma_sdk?
remove third_party/gpsd?
remove third_party/usb_ids (use usbutils)?
remove third_party/clang_format?
remove third_party/webpagereplay?
remove third_party/chromite?
remove third_party/libyuv (libmagickcore5: /usr/lib/x86_64-linux-gnu/ImageMagick-6.7.7/modules-Q16/coders/yuv.so)?
remove third_party/libmtp (link libmtp-dev)?
remove third_party/libc++ (link libc++-dev, maybe only needed for clang build)?
remove third_party/libc++abi (link libc++abi-dev, maybe only needed for clang build)?
remove third_party/libwebm (package libwebm http://www.webmproject.org/code)?
remove third_party/webgl (package webgl http://www.khronos.org/registry/webgl/sdk)?
remove third_party/pyftpdlib (use python-pyftpdlib)?
remove third_party/pywebsocket (disable or use python-mod/pywebsocket)?

follow instructions in third_party/webdriver/README.chromium to generate atoms.*,
  remove third_party/webdriver/pylib/selenium, and use python-selenium

remove base/third_party/xdg_mime (use support in xdg-utils)?

package polymer and use it instead of third_party/polymer
package jstemplate and use it instead of third_party/jstemplate

use system libjingle, libcld2, libphonenumber, libadressinput, cacheinvalidation, dynamic_annotations, angle, smhasher, sfntly, mt19937ar, ...

remove third_party/libXNVCtrl (package currently in contrib, bug #747837)
remove third_party/iccjpeg (currently no library to link against, bug #747839)

remove crypto/third_party/nss?

net/third_party/nss is majorly patched an not likely easy to swap out for system version
base/third_party/icu reproduces stuff from system icu, but uses alternative namespace

remove chrome/test (gyp includes stuff that likely isn't needed from here)?
remove chrome/installer (gyp includes stuff that likely isn't needed from here)?

build with clang.