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

extensions/extensions.gyp

Index: extensions/extensions.gyp
diff --git a/extensions/extensions.gyp b/extensions/extensions.gyp
index 3aae4cb258e6b603f96fce52096d3a347125aac4..5c0c93602ec3037b1d8b9e96f69c710f8ab4728c 100644
--- a/extensions/extensions.gyp
+++ b/extensions/extensions.gyp
@@ -38,7 +38,7 @@
         '<@(extensions_common_mojo_sources)',
       ],
       'conditions': [
-        ['enable_wifi_display==1', {
+        ['proprietary_codecs==1 and enable_wifi_display==1', {
           'sources': [
             '<@(extensions_common_mojo_sources_wifi_display)',
           ],
@@ -186,7 +186,7 @@
             '<@(extensions_browser_sources_linux_nonchromeos)',
           ],
         }],
-        ['enable_wifi_display == 1', {
+        ['proprietary_codecs==1 and enable_wifi_display == 1', {
           'sources': [
             '<@(extensions_browser_sources_wifi_display)',
             '<(SHARED_INTERMEDIATE_DIR)/extensions/common/mojo/wifi_display_session_service.mojom.cc',
@@ -219,8 +219,9 @@
       # Disable c4267 warnings until we fix size_t to int truncations.
       'msvs_disabled_warnings': [ 4267, ],
       'conditions': [
-        ['enable_wifi_display==1', {
+        ['proprietary_codecs==1 and enable_wifi_display==1', {
           'dependencies': [
+            '../third_party/openh264/openh264.gyp:openh264_encoder',
             '../third_party/wds/wds.gyp:libwds',
           ],
           'sources': [