Make chrome_shell_apk build

content/public/test/android/BUILD.gn

 import("//build/config/android/config.gni")
 import("//build/config/android/rules.gni")
 
 # GYP: //content/content_tests.gypi:test_support_content_jni_headers
 generate_jni("test_support_content_jni_headers") {
   jni_package = "content/public/test"
   sources = [
     "javatests/src/org/chromium/content/browser/test/NestedSystemMessageHandler.java",
   ]
 }
 
 # GYP: //content/content_tests.gypi:content_java_test_support
 android_library("content_java_test_support") {
   deps = [
     "//base:base_java",
     "//base:base_java_test_support",
     "//content/public/android:content_java",
   ]
-  DEPRECATED_java_in_dir = "javatests"
+  DEPRECATED_java_in_dir = "javatests/src"
 }