Preparation CL for H264 support in WebRTC.

content/renderer/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
+import("//build/buildflag_header.gni")
 import("//content/renderer/renderer.gni")
 import("//media/media_options.gni")
+import("//third_party/webrtc/build/webrtc.gni")
 
 source_set("renderer") {
   # Only the public target should depend on this. All other targets (even
   # internal content ones) should depend on the public one.
   visibility = [ "//content/public/renderer:renderer_sources" ]
 
   sources = rebase_path(content_renderer_gypi_values.private_renderer_sources,
                         ".",
                         "//content")
 
   configs += [
     "//content:content_implementation",
     "//build/config/compiler:no_size_t_to_int_warning",
     "//content/public/common:mojo_shell_client",
   ]
   defines = []
 
   deps = [
     "//base:i18n",
 
     # TODO(GYP) bug 376846 remove this. This should be inherited from //net but

[brettw, 2016/02/03 22:19:56]

Can you delete this comment? It looks like it applies to your dep but it
doesn't. I think it's obsolete, or at least my intention was lost in time.

...actually it was removed last week! You will just need to merge this file.

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

Merging got rid of it.

     # those don't cross component boundaries.
+    ":renderer_features",
     "//base/allocator",
     "//cc",
     "//cc/blink",
     "//cc/proto",
     "//cc/surfaces",
     "//cc/surfaces:surface_id",
     "//components/scheduler:scheduler",
     "//components/startup_metric_utils/common",
     "//components/url_formatter",
     "//components/webusb",
@@ skipping 197 matching lines @@
   }
 
   if (use_seccomp_bpf) {
     defines += [ "USE_SECCOMP_BPF" ]
   }
 
   if (use_ozone) {
     deps += [ "//ui/ozone" ]
   }
 }
+
+buildflag_header("renderer_features") {
+  header = "renderer_features.h"
+
+  flags = [ "RTC_USE_H264=$rtc_use_h264" ]
+}