[chrome.displaySource] Implement software based H.264 video encoder.

extensions/extensions.gyp

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'includes': [
     'extensions.gypi',
   ],
   'variables': {
     'chromium_code': 1,
@@ skipping 180 matching lines @@
             '<@(extensions_browser_sources_wifi_display)',
             '<(SHARED_INTERMEDIATE_DIR)/extensions/common/mojo/wifi_display_session_service.mojom.cc',
             '<(SHARED_INTERMEDIATE_DIR)/extensions/common/mojo/wifi_display_session_service.mojom.h',
           ],
         }],
       ],
       # Disable c4267 warnings until we fix size_t to int truncations.
       'msvs_disabled_warnings': [ 4267, ],
     },
     {
       # GN version: //extensions/renderer

[hbos_chromium, 2016/04/28 09:02:33]

Make a similar change to the GN version

[e_hakkinen, 2016/04/28 13:47:39]

Done.

       'target_name': 'extensions_renderer',
       'type': 'static_library',
       'dependencies': [
         'extensions_resources.gyp:extensions_resources',
         '../components/components.gyp:guest_view_renderer',
         '../content/content.gyp:content_common',
         '../content/content.gyp:content_resources',
         '../gin/gin.gyp:gin',
         '../mojo/mojo_public.gyp:mojo_js_bindings',
         '../third_party/WebKit/public/blink.gyp:blink',
       ],
       'include_dirs': [
         '..',
       ],
       'sources': [
         '<@(extensions_renderer_sources)',
       ],
       # Disable c4267 warnings until we fix size_t to int truncations.
       'msvs_disabled_warnings': [ 4267, ],
       'conditions': [
         ['enable_wifi_display==1', {
           'dependencies': [
             '../third_party/wds/wds.gyp:libwds',
           ],
           'sources': [
             '<@(extensions_renderer_sources_wifi_display)',
           ],
+          'conditions': [
+            ['use_openh264==1', {

[hbos_chromium, 2016/04/28 09:02:33]

I added the use_openh264 flag so that I could control if openh264 is build in
chromium. While writing the build files for third_party/openh264 I changed the
default value of use_openh264 to true to make sure it built on the bots (and
then changed back to false before landing).

I don't know about enable_wifi_display, but I don't think any bots override
use_openh264, which means your code is not getting tested by our bots. This flag
is so far not used for anything except adding a dependency to the All targets
(which is probably a dependency I should remove now that the build files are
healthy, only targets using the library should have a direct dependency on it,
such as this one).

I was going to use the flag, but for the third_party/webrtc encoder using
openh264 that I wrote (h264_encoder_impl.cc) I had to use a flag defined in the
webrtc repo instead (rtc_use_h264). We made this flag default to
proprietary_codecs, which is used in Chrome Official build and other bots.

You probably want to use a flag that defaults to proprietaty_codecs too? You
could modify use_openh264 to default to proprietary_codecs or create a new flag
that defaults to it. That way your code is used without extra flags.

I'm debating removing use_openh264 since even if its false openh264 could be
used (if rtc_use_h264=1); confusing.

[hbos_chromium, 2016/04/28 09:22:15]

If this does not apply because this is an extension and you don't mind the extra
flag you can leave this as-is. I don't know the background.

[e_hakkinen, 2016/04/28 13:47:39]

The code is not used without an extra flags anyway as enable_wifi_display is
false by default.

As the software fallback is quite important part of WiFi Display stack, I just
removed the condition altogether.

[hbos_chromium, 2016/04/28 14:27:29]

There are reasons for why third_party/openh264 is not built by default. We need
to be careful about adding dependency on it without special flags. It is already
behind one flag, but I think you should add a new flag and default it to
proprietary_codecs, making openh264 an optional part of this extension.

+              'defines': ['USE_OPENH264=1'],
+              'dependencies': [
+                '../third_party/openh264/openh264.gyp:openh264_encoder',
+              ]
+            }]
+          ]
         }],
       ],
     },
     {
       # GN version: //extensions/utility
       'target_name': 'extensions_utility',
       'type': 'static_library',
       'dependencies': [
         '../content/content.gyp:content_common',
         '../content/content.gyp:content_utility',
@@ skipping 80 matching lines @@
               '<(SHARED_INTERMEDIATE_DIR)/blink/devtools_resources.pak',
             ],
             'pak_output': '<(PRODUCT_DIR)/extensions_shell_and_test.pak',
           },
           'includes': [ '../build/repack_action.gypi' ],
         },
       ],
     },
   ]
 }