Add browsertests for VibrationManager java impl on android.

content/public/android/BUILD.gn

Index: content/public/android/BUILD.gn
diff --git a/content/public/android/BUILD.gn b/content/public/android/BUILD.gn
index dc0d3f5a828f5184d3493beaa3a128638d1b7999..e8a086e83b866d65b973598a9af0576f9a2ecaa7 100644
--- a/content/public/android/BUILD.gn
+++ b/content/public/android/BUILD.gn
@@ -185,6 +185,8 @@ android_library("content_javatests") {
     "//content/shell/android:content_shell_java_resources",
     "//content/shell/android:content_shell_apk_java",
     "//content/shell/android:content_shell_test_java",
+    "//device/vibration/android:vibration_manager_android",

[Ted C, 2015/11/02 23:16:47]

are these actually needed?  It looks like they are transitvely included by
content_java_test_support

content_java_test_support -> //content/public/android:content_java ->
"//device/vibration/android:vibration_manager_android" &&
"//device/vibration:mojo_bindings_java",

[leonhsl(Using Gerrit), 2015/11/03 08:56:25]

Yeah the deps are there.. But without this change the android gn trybot always
failed because VibrationManagerImpl class definition can't be located..

+    "//device/vibration:mojo_bindings_java",
     "//media/base/android:media_java",
     "//mojo/android:system_java",
     "//net/android:net_java",