Preparation CL for H264 support in WebRTC.

content/content.gyp

Index: content/content.gyp
diff --git a/content/content.gyp b/content/content.gyp
index ecf8e4d3e11e8f492d53d1cdf69d8cb7c20fad4b..96e8900bbc2cb1827ba29eff9002caad66b945c4 100644
--- a/content/content.gyp
+++ b/content/content.gyp
@@ -21,6 +21,30 @@
       }],
     ],
   },
+  'targets': [
+    {
+      # GN version: //content/renderer:renderer_features
+      'target_name': 'renderer_features',
+      'includes': [
+        '../build/buildflag_header.gypi',
+        '../third_party/webrtc/build/common.gypi',
+      ],
+      'conditions': [
+        # This conditional looks insane, but without it |rtc_use_h264| is not

[brettw, 2016/02/03 22:19:55]

I don't really care about this too much, but I *think* the right solution is to
replace the outer conditions with another variables block:
  'variables': {
     'variables': {
        'buildflag_hea...<other stuff>
      }
   }
Can you see if that fixes the problem before checking in?

[hbos_chromium, 2016/02/04 10:47:32]

I tried that (including 'var': '<(var)' in the outer 'variables'), but it didn't
work. Undefined variable rtc_use_h264. GYP is horrendous isn't it. Keeping it
this way.

+        # recognized as defined. Might have something to do with scopes. Moving
+        # the inclusion of third_party/webrtc/build/common.gypi to outside of
+        # 'targets' is not an option, then we get compile errors.
+        ['1==1', {
+          'variables': {
+            'buildflag_header_path': 'content/renderer/renderer_features.h',
+            'buildflag_flags': [
+              'RTC_USE_H264=<(rtc_use_h264)',
+            ],
+          },
+        }],
+      ],
+    },
+  ],
   'conditions': [
     ['OS != "ios"', {
       'includes': [
@@ -262,6 +286,7 @@
                 'content_child',
                 'content_common',
                 'content_resources',
+                'renderer_features',
               ],
               'export_dependent_settings': [
                 'content_common',
@@ -301,6 +326,7 @@
           'variables': { 'enable_wexit_time_destructors': 1, },
           'dependencies': [
             'content_resources',
+            'renderer_features',
           ],
           'conditions': [
             ['chromium_enable_vtune_jit_for_v8==1', {