Add fallback to use 'templates-sdk' when no templates specified
and the build is targeting devsite.
This is necessary for google3 builds so they can stop referencing
copied versions of the template files, because it's too messy to
export all the template files into a location they can directly
reference for the 'templatesdir' argument. So instead, they now
just leave off that argument in their doclava command.

Change-Id: I9d8edad3b9f65313887779a7b720baa04fc90a10
diff --git a/src/com/google/doclava/Doclava.java b/src/com/google/doclava/Doclava.java
index 8fc0b4f..ae28048 100644
--- a/src/com/google/doclava/Doclava.java
+++ b/src/com/google/doclava/Doclava.java
@@ -359,6 +359,12 @@
       for (String tmpl : templates) {
         resourceLoaders.add(new FileSystemResourceLoader(tmpl));
       }
+      // If no custom template path is provided, and this is a devsite build,
+      // then use the bundled templates-sdk/ files by default
+      if (templates.isEmpty() && USE_DEVSITE_LOCALE_OUTPUT_PATHS) {
+        resourceLoaders.add(new ClassResourceLoader(Doclava.class, "/assets/templates-sdk"));
+        System.out.println("\n#########  OK, Using templates-sdk ############\n");
+      }
 
       templates = ClearPage.getBundledTemplateDirs();
       for (String tmpl : templates) {