GN: Add mojo_shell_tests, get more things working on android

mojo/services/native_viewport/BUILD.gn

Index: mojo/services/native_viewport/BUILD.gn
diff --git a/mojo/services/native_viewport/BUILD.gn b/mojo/services/native_viewport/BUILD.gn
index 31113ce7f9ccdfb44e5ef54d408dc8ed888ff8af..9513af944382cb458b3a2ee8e1616bf71b1906c0 100644
--- a/mojo/services/native_viewport/BUILD.gn
+++ b/mojo/services/native_viewport/BUILD.gn
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import("//build/config/ui.gni")
+import("//mojo/system.gni")
 
 component("native_viewport") {
   output_name = "mojo_native_viewport"
@@ -21,6 +22,7 @@ component("native_viewport") {
     "//mojo/services/public/cpp/input_events",
     "//mojo/services/public/interfaces/native_viewport",
   ]
+  deps += mojo_system_for_component
 
   defines = [ "MOJO_NATIVE_VIEWPORT_IMPLEMENTATION" ]
 
@@ -56,8 +58,4 @@ component("native_viewport") {
   if (use_ozone) {
     sources += [ "native_viewport_ozone.cc" ]
   }
-
-  if (is_component_build) {
-    deps += [ "//mojo/system" ]
-  }
 }