Add blimp to root GN check_targets

content/app/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/chrome_build.gni")
+import("//build/config/features.gni")
 
 content_app_sources = [
   "android/app_jni_registrar.cc",
   "android/app_jni_registrar.h",
   "android/child_process_service.cc",
   "android/child_process_service.h",
   "android/content_jni_onload.cc",
   "android/content_main.cc",
   "android/content_main.h",
   "android/download_main.cc",
@@ skipping 29 matching lines @@
   content_app_deps += [
     "//content/public/android:jni",
     "//device/usb",
     "//device/vibration",
     "//skia",
     "//third_party/android_tools:cpu_features",
     "//ui/android",
   ]
 }
 
+if (enable_plugins) {

[Dirk Pranke, 2016/04/28 00:25:40]

For posterity, I think in order to address brettw's comments in #59 and #60, I
think we should change this to if (is_linux && enable_plugins), and not add the
dependency from blimp to //content/public/child. I think if we do what I
suggest, we keep the dependencies in blimp "right" and make content/app
"slightly more right", whereas if we do brettw's suggestion in #60, we make
blimp more confusing and don't make content any less confusing. 

[nyquist, 2016/04/28 00:56:00]

I implemented both... So, in patch set 17 below you'll find the latest and
greatest, which for now is your suggestion of adding is_linux.

+  content_app_deps += [ "//content/ppapi_plugin:ppapi_plugin_sources" ]
+}
+
 content_app_extra_configs = [
   "//build/config/compiler:wexit_time_destructors",
   "//content:content_implementation",
   "//content/public/common:mojo_shell_client",
   "//v8:external_startup_data",
 ]
 
 if (!is_multi_dll_chrome) {
   content_app_deps += [ "//content/gpu:gpu_sources" ]
 }
@@ skipping 39 matching lines @@
   source_set("child") {
     visibility = [ "//content/public/app:child" ]
 
     sources = content_app_sources
     configs += content_app_extra_configs
     deps = content_app_deps
 
     defines = [ "CHROME_MULTIPLE_DLL_CHILD" ]
   }
 }