GN: Enable blink and (nearly) all of content in android build

content/test/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/features.gni")
 import("//build/config/ui.gni")
 
 content_tests_gypi_values = exec_script(
     "//build/gypi_to_gn.py",
     [ rebase_path("../content_tests.gypi"),
@@ skipping 145 matching lines @@
       ":test_support",
       "//cc",
       "//cc/blink",
       "//content/public/common",
       "//skia",
       "//v8",
       "//ui/accessibility:ax_gen",
     ]
 
     if (is_android) {
-      #deps += [ "test_support_content_jni_headers" ]  TODO(GYP)
+      deps += [ ":jni" ]
     }
   }
 
+  if (is_android) {
+    import("//build/config/android/rules.gni")
+
+    generate_jni("jni") {
+      sources = [ "../public/test/android/javatests/src/org/chromium/content/browser/test/NestedSystemMessageHandler.java" ]
+      jni_package = "content/public/test"
+    }
+  }
 }  # !is_ios
 
 # TODO(GYP): Unit test targets