rtc_use_h264 flag for building OpenH264/FFmpeg

webrtc/build/common.gypi

Index: webrtc/build/common.gypi
diff --git a/webrtc/build/common.gypi b/webrtc/build/common.gypi
index 14f7e9a4a368ba300dc56e0d7f5bbad9617ac0ae..e82fe5cd65b001c337964974f5b16f06b7532737 100644
--- a/webrtc/build/common.gypi
+++ b/webrtc/build/common.gypi
@@ -137,18 +137,22 @@
     # Enabling this may break interop with Android clients that support H264.
     'use_objc_h264%': 0,
 
-    # Enable this to build H.264 encoder/decoder using third party libraries.
-    # Encoding uses OpenH264 and decoding uses FFmpeg. Because of this, OpenH264
-    # and FFmpeg have to be correctly enabled separately.
-    # - use_openh264=1 is required for OpenH264 targets to be defined.
-    # - ffmpeg_branding=Chrome is one way to support H.264 decoding in FFmpeg.
-    #   FFmpeg can be built with/without H.264 support, see 'ffmpeg_branding'.
-    #   Without it, it compiles but H264DecoderImpl fails to initialize.
+    # Enable this to build OpenH264 encoder/FFmpeg decoder. This is supported on
+    # all platforms except iOS. Because FFmpeg can be built with/without H.264
+    # support, |ffmpeg_branding| has to separately be set to a value that
+    # includes H.264, for example "Chrome". If FFmpeg is built without H.264,
+    # compilation succeeds but |H264DecoderImpl| fails to initialize.
     # CHECK THE OPENH264, FFMPEG AND H.264 LICENSES/PATENTS BEFORE BUILDING.
     # http://www.openh264.org, https://www.ffmpeg.org/
-    'use_third_party_h264%': 0,  # TODO(hbos): To be used in follow-up CL(s).
+#    'use_h264%': 0,  # TODO(hbos): enc/dec in follow up CL(s).

[kjellander_webrtc, 2016/01/20 19:28:45]

You don't need to define this here if you define it in both the if and the else
clause below.
Or is that why you've commented it? Either way this file needs to be updated.

[hbos, 2016/01/21 10:00:01]

(Since I couldn't remember supplement.gypi I did the if-else here, the commented
out line being how it should have been without the if-else)

 
     'conditions': [
+      ['OS!="ios"', {
+        'use_h264%': 1,
+      }, {
+        'use_h264%': 0,
+      }],
+
       ['build_with_chromium==1', {
         # Exclude pulse audio on Chromium since its prerequisites don't require
         # pulse audio.