GN: Build libvpx

DEPS

 # This file is automatically processed to create .DEPS.git which is the file
 # that gclient uses under git.
 #
 # See http://code.google.com/p/chromium/wiki/UsingGit
 #
 # To test manually, run:
 #   python tools/deps2git/deps2git.py -o .DEPS.git -w <gclientdir>
 # where <gcliendir> is the absolute path to the directory containing the
 # .gclient file (the parent of 'src').
 #
@@ skipping 15 matching lines @@
   'llvm_git': 'https://llvm.googlesource.com',
   'libcxx_revision': '48198f9110397fff47fe7c37cbfa296be7d44d3d',
   'libcxxabi_revision': '4ad1009ab3a59fa7a6896d74d5e4de5885697f95',
   'webkit_trunk': 'http://src.chromium.org/blink/trunk',
   'webkit_revision': '01025b523bac1a59fa91a10d5d49f969ed24000d', # from svn revision 181983
   'chromium_git': 'https://chromium.googlesource.com',
   'chromiumos_git': 'https://chromium.googlesource.com/chromiumos',
   'pdfium_git': 'https://pdfium.googlesource.com',
   'skia_git': 'https://skia.googlesource.com',
   'boringssl_git': 'https://boringssl.googlesource.com',
-  'libvpx_revision': 'd95585fb0ec024f6abd96f7b02e0df58019d46af', # r291859
+  'libvpx_revision': '4947d55857acf2bf968016a7a00fe2b10fd52131',
   'sfntly_revision': '1bdaae8fc788a5ac8936d68bf24f37d977a13dac',
   'skia_revision': '595aa05efcb504e85358b8d328ac4a9fa1c46e2e',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and V8 without interference from each other.
   'v8_branch': 'trunk',
   'v8_revision': 'b376fed08cb9d90a3f67f655adf63c4b35feb106', # from svn revision 23929
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling WebRTC
   # and V8 without interference from each other.
@@ skipping 745 matching lines @@
     # corresponding .py files have already been deleted.
     'name': 'remove_stale_pyc_files',
     'pattern': 'src/tools/.*\\.py',
     'action': [
         'python',
         'src/tools/remove_stale_pyc_files.py',
         'src/tools',
     ],
   },
 ]