New FFmpeg public API headers to match our source tarball in deps.

third_party/ffmpeg/README.chromium

 This contains FFmpeg's public header files from the output of a "make install"
-command.  The header files are from FFmpeg revision 18286.
+command.  The header files are from Chromium's copy of FFmpeg.
 
 Steps to reproduce:
-  1) If on Windows, refer to http://ffmpeg.arrozcru.org for environment setup
-  2) Check out FFmpeg from their repository
-  3) ./configure --prefix=/path/to/chrome/src/third_party/ffmpeg
-  4) make && make install
-  5) Remove bin and lib folders, leaving the include folder behind
+  1) If on Windows, refer to our MinGW/MSYS environment setup:
+       http://src.chromium.org/viewvc/chrome/trunk/deps/third_party/mingw/
+  2) Grab Chromium's copy of FFmpeg:
+       http://src.chromium.org/viewvc/chrome/trunk/deps/third_party/ffmpeg/
+  3) Follow the instructions to build and install.
+  4) Go to your install location and copy the following into the Chromium tree:
+       /path/to/install/include/libavcodec
+       /path/to/install/include/libavformat
+       /path/to/install/include/libavutil
 
 The project contains some hand-written DEF files used to generate import
 libraries to permit dynamically loading FFmpeg.  The libaries are linked in
 using /DELAYLOAD to avoid having the DLLs present at run-time.
 
 We don't use the import libraries generated from building FFmpeg because they
 export every method by ordinal, which makes binary compatability with different
 builds of FFmpeg difficult if not impossible.  Furthermore, it is much easier
 to update a DEF file instead of rebuilding FFmpeg to generate new import
 libraries.
-