Roll FFmpeg for M45.

DEPS

 # This file is used to manage the dependencies of the Chromium src repo. It is
 # used by gclient to determine what version of each dependency to check out, and
 # where.
 #
 # For more information, please refer to the official documentation:
 #   https://sites.google.com/a/chromium.org/dev/developers/how-tos/get-the-code
 #
 # When adding a new dependency, please update the top-level .gitignore file
 # to list the dependency's destination directory.
 #
@@ skipping 168 matching lines @@
   'src/third_party/webgl/src':
    Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + '8986f8bfa84547b1a30a9256ebdd665024d68d71',
 
   'src/third_party/webdriver/pylib':
     Var('chromium_git') + '/external/selenium/py.git' + '@' + '5fd78261a75fe08d27ca4835fb6c5ce4b42275bd',
 
   'src/third_party/libvpx':
    Var('chromium_git') + '/chromium/deps/libvpx.git' + '@' +  Var('libvpx_revision'),
 
   'src/third_party/ffmpeg':
-   Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + '1f2f7df0f4005fb620342d847bbaa1ec54122c68',
+   Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + 'f76066ad9f4aea07a53890b54d24cc22830b9efd',
 
   'src/third_party/libjingle/source/talk':
     Var('chromium_git') + '/external/webrtc/trunk/talk.git' + '@' + 'f7c923ddc729dc7f002b0e194ab72b661f932c00', # commit position 9564
 
   'src/third_party/usrsctp/usrsctplib':
     Var('chromium_git') + '/external/usrsctplib.git' + '@' + '36444a999739e9e408f8f587cb4c3ffeef2e50ac', # from svn revision 9215
 
   'src/third_party/libsrtp':
    Var('chromium_git') + '/chromium/deps/libsrtp.git' + '@' + '9c53f858cddd4d890e405e91ff3af0b48dfd90e6', # from svn revision 295151
 
@@ skipping 589 matching lines @@
     # migration completes (let's say Sep 1 2014).
     'name': 'check_git_config',
     'pattern': '.',
     'action': [
         'python',
         'src/tools/check_git_config.py',
         '--running-as-hook',
     ],
   },
 ]