Fix mojo_android_application when there is no java sources.

mojo/public/mojo_application.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.
 
 import("//build/module_args/mojo.gni")
 import("mojo.gni")
 import("mojo_sdk.gni")
 
 # Generate a binary mojo application.The parameters of this template are those
 # of a shared library.
@@ skipping 309 matching lines @@
   #   sources (optional): The c++ sources.
   #   deps (optional): The c++ dependencies.
   #   java_sources (optional): The java sources.
   #   java_deps (optional): The java dependencies.
   #   jni_package (optional): The c++ package for the generated jni headers.
   #   output_name (optional): override for the output file name
   #   public_deps / data_deps (optional): Dependencies.
   template("mojo_android_application") {
     shared_library_name = "__${target_name}_lib"
     library_basename = "lib${shared_library_name}.so"
-    generate_jni_name = "__${target_name}_jni"
-    java_library_name = "__${target_name}_java"
+    if (defined(invoker.jni_package)) {
+      assert(defined(invoker.java_sources))
+      generate_jni_name = "__${target_name}_jni"
+    }
+    if (defined(invoker.java_sources)) {
+      java_library_name = "__${target_name}_java"
+    }
     android_standalone_library_name = "__${target_name}_java_lib"
     dex_output_path = "${target_gen_dir}/${target_name}.dex"
     zip_action_name = "__${target_name}_zip"
     zip_action_output = "${target_gen_dir}/${target_name}.zip"
     copy_symbols_target = "__${target_name}_copy_symbols"
     final_target_name = target_name
 
-    if (defined(invoker.java_sources) && defined(invoker.jni_package)) {
+    if (defined(invoker.jni_package)) {
       generate_jni(generate_jni_name) {
         visibility = [ ":${shared_library_name}" ]
 
         sources = invoker.java_sources
         jni_package = invoker.jni_package
       }
     }
 
     shared_library(shared_library_name) {
       visibility = [
         ":${copy_symbols_target}",
         ":${zip_action_name}",
       ]
 
       if (defined(invoker.sources)) {
         sources = invoker.sources
       }
 
       deps = []
-      if (defined(invoker.java_sources) && defined(invoker.jni_package)) {
+      if (defined(invoker.jni_package)) {
         deps += [ ":${generate_jni_name}" ]
       }
       if (defined(invoker.deps)) {
         deps += invoker.deps
       }
     }
 
     copy(copy_symbols_target) {
       visibility = [ ":${final_target_name}" ]
       deps = [
         ":${shared_library_name}",
       ]
 
       sources = [
         "${root_out_dir}/${library_basename}",
       ]
       outputs = [
         "${root_out_dir}/symbols/${library_basename}",
       ]
     }
 
-    android_library(java_library_name) {
-      visibility = [ ":*" ]
+    if (defined(invoker.java_sources)) {
+      android_library(java_library_name) {
+        visibility = [ ":*" ]
 
-      if (defined(invoker.java_sources)) {
         java_files = invoker.java_sources
-      }
 
-      if (defined(invoker.java_deps)) {
-        deps = invoker.java_deps
+        if (defined(invoker.java_deps)) {
+          deps = invoker.java_deps
+        }
       }
     }
 
     android_standalone_library(android_standalone_library_name) {
-      deps = [
-        ":${java_library_name}",
-      ]
+      deps = []
+
+      if (defined(invoker.java_sources)) {
+        deps += [ ":${java_library_name}" ]
+      }
 
       if (defined(invoker.java_deps)) {
         deps += invoker.java_deps
       }
 
       dex_path = dex_output_path
     }
 
     action(zip_action_name) {
       visibility = [ ":${final_target_name}" ]
@@ skipping 57 matching lines @@
       deps = [
         ":${copy_symbols_target}",
       ]
 
       public_deps = [
         ":${zip_action_name}",
       ]
     }
   }
 }