Handle APKs with only loadable modules.

Update the checks in rules.gni so that _native_libs_file_arg is set in
the same cases that it is used; otherwise APKs that contain a loadable
module but not a "main" shared library fail.

Change-Id: I88e0c169199af9625dcb7750f9bcd0a9b3dca4b7
Reviewed-on: https://chromium-review.googlesource.com/1238781Reviewed-by: Eric Stevenson <estevenson@chromium.org>
Commit-Queue: Richard Coles <torne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593277}

build/config/android/rules.gni

@@ -2546,17 +2546,6 @@ if (enable_java_templates) {
       _final_deps += [ ":$_java_target" ]
     }
 
-    _all_native_libs_deps = []
-    if (_native_libs_deps != []) {
-      _native_libs_file_arg_dep = ":$_build_config_target"
-      if (!_is_bundle_module) {
-        _native_libs_file_arg =
-            "@FileArg($_rebased_build_config:native:libraries)"
-      }
-      _all_native_libs_deps += _native_libs_deps + _extra_native_libs_deps +
-                               [ _native_libs_file_arg_dep ]
-    }
-
     _extra_native_libs_even_when_incremental = []
     assert(_extra_native_libs_even_when_incremental == [])  # Mark as used.
     if (_native_libs_deps != []) {
@@ -2572,6 +2561,18 @@ if (enable_java_templates) {
       _extra_native_libs_even_when_incremental += invoker.loadable_modules
     }
 
+    _all_native_libs_deps = []
+    if (_native_libs_deps != [] ||
+        _extra_native_libs_even_when_incremental != []) {
+      _native_libs_file_arg_dep = ":$_build_config_target"
+      if (!_is_bundle_module) {
+        _native_libs_file_arg =
+            "@FileArg($_rebased_build_config:native:libraries)"
+      }
+      _all_native_libs_deps += _native_libs_deps + _extra_native_libs_deps +
+                               [ _native_libs_file_arg_dep ]
+    }
+
     # Generate .apk.jar.info files if needed.
     if (defined(invoker.name)) {
       _apk_jar_info_target = "${target_name}__apk_jar_info"