gn BUILD fixes for disabling enable_extensions and use_ash feature flags.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 96fa27f25d35736cefbe6d9d5c59f4ff092428b7..5a461e542a86c6284d1be35da67d060183d08bf4 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -144,8 +144,6 @@ group("both_gn_and_gyp") {
       "//chrome/test:interactive_ui_tests",
       "//chrome/test:sync_integration_tests",
       "//chrome/test/chromedriver:chromedriver_unittests",
-      "//extensions:extensions_browsertests",
-      "//extensions:extensions_unittests",
       "//gpu/gles2_conform_support:gles2_conform_test",
       "//jingle:jingle_unittests",
       "//net:hpack_example_generator",
@@ -253,7 +251,12 @@ group("both_gn_and_gyp") {
   deps += root_extra_deps
 
   if (enable_extensions) {
-    deps += [ "//extensions/shell:app_shell_unittests" ]
+    deps += [
+      "//extensions:extensions_browsertests",
+      "//extensions:extensions_unittests",
+      "//extensions/shell:app_shell",
+      "//extensions/shell:app_shell_unittests",
+    ]
   }
 
   if (enable_media_router) {
@@ -270,13 +273,17 @@ group("both_gn_and_gyp") {
 
   if (use_aura) {
     deps += [
-      "//ash:ash_shell_with_content",
-      "//ash:ash_unittests",
       "//ui/app_list/presenter:app_list_presenter_unittests",
       "//ui/aura:aura_unittests",
       "//ui/aura:demo",
       "//ui/wm:wm_unittests",
     ]
+    if (use_ash) {
+      deps += [
+        "//ash:ash_shell_with_content",
+        "//ash:ash_unittests",
+      ]
+    }
   }
 
   if (use_ozone) {
@@ -483,11 +490,6 @@ group("both_gn_and_gyp") {
       # into chromium.
       deps += [ "//third_party/angle/src/tests:angle_end2end_tests" ]
     }
-
-    if (enable_extensions) {
-      deps += [ "//extensions/shell:app_shell" ]
-    }
-
     if (enable_nacl) {
       deps += [ "//components/nacl/loader:nacl_loader_unittests" ]
 
@@ -651,11 +653,13 @@ group("gn_only") {
       "//components/mus/demo",
       "//components/mus/ws:tests",
       "//components/resource_provider:resource_provider_unittests",
-      "//mash:all",
       "//media/mojo/services:media_mojo_shell_unittests",
       "//mojo",
       "//ui/views/mus:views_mus_unittests",
     ]
+    if (use_ash) {
+      deps += [ "//mash:all" ]
+    }
   }
 
   if (is_linux && !is_chromeos && !is_chromecast) {