Android: enable/disable WebRTC HW H264 with a flag.

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 52ecbe3983d0a68db6e374cbd56daa9cee57a35a..bc1238ec649d126ab286eaea2e4c7edae1f62314 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -666,6 +666,19 @@ const FeatureEntry::Choice kSecurityVerboseChoices[] = {
 };
 #endif  // defined(OS_MACOSX)
 
+#if defined(ENABLE_WEBRTC)
+const FeatureEntry::Choice kDisableWebRtcHWEncodingChoices[] = {
+    {IDS_GENERIC_EXPERIMENT_CHOICE_DEFAULT, "", ""},
+    {IDS_FLAGS_WEBRTC_HW_ENCODING_ALL, switches::kDisableWebRtcHWEncoding, ""},
+    {IDS_FLAGS_WEBRTC_HW_ENCODING_VPX, switches::kDisableWebRtcHWEncoding,
+     switches::kDisableWebRtcHWEncodingVPx},
+    {IDS_FLAGS_WEBRTC_HW_ENCODING_H264, switches::kDisableWebRtcHWEncoding,
+     switches::kDisableWebRtcHWEncodingH264},
+    {IDS_FLAGS_WEBRTC_HW_ENCODING_NONE, switches::kDisableWebRtcHWEncoding,
+     switches::kDisableWebRtcHWEncodingNone},

[watk, 2016/10/01 01:06:53]

The double negative is confusing. Can it be called kEnableWebRtcHWEncoding?

[braveyao, 2016/10/03 23:50:14]

Yes it's a bit confusing. But it works as a pair to
'switches::kDisableWebRtcHWDecoding'. If I recall it correctly, they are both
evolved from 'kEnableWebRtcHWEncoding/Decoding' quite a while ago.
CrOS needs it to be 'kDisableWebRtcHWEncoding' as HW codec is the first choice
on it. Android may need it soon. So I suppose this should be OK. WDYT?

+};
+#endif
+
 // RECORDING USER METRICS FOR FLAGS:
 // -----------------------------------------------------------------------------
 // The first line of the entry is the internal name.
@@ -722,7 +735,7 @@ const FeatureEntry kFeatureEntries[] = {
      SINGLE_DISABLE_VALUE_TYPE(switches::kDisableWebRtcHWDecoding)},
     {"disable-webrtc-hw-encoding", IDS_FLAGS_WEBRTC_HW_ENCODING_NAME,
      IDS_FLAGS_WEBRTC_HW_ENCODING_DESCRIPTION, kOsAndroid | kOsCrOS,
-     SINGLE_DISABLE_VALUE_TYPE(switches::kDisableWebRtcHWEncoding)},
+     MULTI_VALUE_TYPE(kDisableWebRtcHWEncodingChoices)},
     {"enable-webrtc-stun-origin", IDS_FLAGS_WEBRTC_STUN_ORIGIN_NAME,
      IDS_FLAGS_WEBRTC_STUN_ORIGIN_DESCRIPTION, kOsAll,
      SINGLE_VALUE_TYPE(switches::kEnableWebRtcStunOrigin)},