Aura on Android: Compile extensions gn target.

build/config/features.gni

 # 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.
 
 # This file contains Chrome-feature-related build flags (see ui.gni for
 # UI-related ones). These should theoretically be moved to the build files of
 # the features themselves.
 #
 # However, today we have many "bad" dependencies on some of these flags from,
 # e.g. base, so they need to be global to match the GYP configuration. Also,
 # anything that needs a grit define must be in either this file or ui.gni.
 #
 # PLEASE TRY TO AVOID ADDING FLAGS TO THIS FILE in cases where grit isn't
 # required. See the declare_args block of BUILDCONFIG.gn for advice on how
 # to set up feature flags.
 
 import("//build/config/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
 declare_args() {
   # Multicast DNS.
   enable_mdns = is_win || is_linux
 
-  enable_plugins = (!is_android && !is_ios) || is_chromecast
+  # We enable plugins on android if use_aura has been explicitly set to true.
+  # use_aura is assigned a value in ui.gni, so it will be undefined here unless

[brettw, 2015/11/12 18:56:27]

The fact that build args are set globally is a bug I'd like to fix. The global
build args should only be set after the corresponding thing is in a declare_args
block. So please don't write code that depends on this behavior.

We could move stuff around to express this nicely. But it doesn't follow to me
that if I enable aura on Android that I get plugins support. These seems sort of
independent, it just so happens that you're only bothering to implement plugins
on aura. So maybe just leave aura out of the defaults and have people explicitly
enable plugins on android if they want them.

If we do that you should note in the comment that it's supported on Android only
in aura.

[Hadi, 2015/11/17 16:49:58]

Removed the changes to features.gni per internal discussion. Planning to address
this change and similar changes to build config in a separate CL.

+  # it was explicitly provided in the build arguments.
+  enable_plugins = (!is_android && !is_ios) || is_chromecast ||
+                   (defined(use_aura) && use_aura)
   enable_pdf = !is_android && !is_ios && !is_chromecast
 
   # Enables Native Client support.
   # TODO(GYP): Get NaCl linking on other platforms.
   # Also, see if we can always get rid of enable_nacl_untrusted and
   # enable_pnacl and always build them if enable_nacl is true.
   # The "is_nacl" part of the condition is needed to ensure that
   # the untrusted code is built properly; arguably it should be
   # guarded by "is_nacl" directly rather than enable_nacl_untrusted, but
   # this will go away when Mac and Win are working and we can just use
@@ skipping 157 matching lines @@
 # Option controlling the use of GConf (the classic GNOME configuration
 # system).
 use_gconf = is_linux && !is_chromeos && !is_chromecast
 
 # Whether to back up data before sync.
 enable_pre_sync_backup = is_win || is_mac || (is_linux && !is_chromeos)
 
 # Enable WebVR support by default on Android
 # Still requires command line flag to access API
 enable_webvr = is_android