Roll chromium_revision 280876:281479
Roll chromium_revision 280876:281479

No significant DEPS changes in this roll, only some changes in how clang_format is downloaded. clang_format changes based on https://webrtc-codereview.appspot.com/20829004 which was reverted.

Review URL: https://webrtc-codereview.appspot.com/19929004

git-svn-id: 917f5d3ca488f358c4d40eaec14422cf392ccec9@6636 4adac7df-926f-26a2-2b94-8c16560cd09d

mwgoldsmith/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,mwgoldsmith/ilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,mwgoldsmith/ilbc,mwgoldsmith/ilbc,mwgoldsmith/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,mwgoldsmith/ilbc,mwgoldsmith/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,mwgoldsmith/libilbc,ShiftMediaProject/libilbc