android: Add template to export sandboxed service

chrome/android/java/AndroidManifest.xml

Index: chrome/android/java/AndroidManifest.xml
diff --git a/chrome/android/java/AndroidManifest.xml b/chrome/android/java/AndroidManifest.xml
index e06efab5062162208581e3077aaba24c49a7e6f1..bc53a92b391bcbde3cdac28767dbea7a91ff4702 100644
--- a/chrome/android/java/AndroidManifest.xml
+++ b/chrome/android/java/AndroidManifest.xml
@@ -624,7 +624,9 @@ by a child template that "extends" this file.
             android:process=":sandboxed_process{{ i }}"
             android:permission="{{ manifest_package }}.permission.CHILD_SERVICE"
             android:isolatedProcess="true"
-            android:exported="false" />
+            android:exported="{{sandboxed_service_exported|default(false)}}"
+            tools:ignore="ExportedService"

[mnaganov (inactive), 2016/01/26 18:25:50]

I guess this is only needed when the service is exported. But maybe it doesn't
harm when it's not.

[Robert Sesek, 2016/01/26 18:30:39]

It would be bad if android:exported="true" and andriod:externalService="false"
AND we were to turn on multiprocess. But if multiprocess is always going to have
externalService="true", then I think that's OK. Though it's probably safest, and
best for tooling, if the tools:ignore were wrapped in a condition gated on
externalService.

[boliu, 2016/01/26 18:58:03]

Couldn't figure out how to do jinja var with space in gn. So just wrapped the
tools:ignore part in an if instead.

+            {{sandboxed_service_extra_flags|default('')}} />
         {% endfor %}
 
         {% set num_privileged_services = 3 %}