Write a phony target for the top-level directory of a create_bundle target.

tools/gn/bundle_data.h

Index: tools/gn/bundle_data.h
diff --git a/tools/gn/bundle_data.h b/tools/gn/bundle_data.h
index e78589e9e91cfce01f68a10928cafe92732965e9..d589a6dc9115f0dede906af034ec0dd535cf3e2b 100644
--- a/tools/gn/bundle_data.h
+++ b/tools/gn/bundle_data.h
@@ -64,6 +64,12 @@ class BundleData {
   // asset_catalog_sources() is not empty.
   SourceFile GetCompiledAssetCatalogPath() const;
 
+  // Returns the path to the top-level directory of the bundle. This is
+  // based on root_dir(), but since that can be Bundle.app/Contents/ or
+  // any other subpath, this is just the most top-level directory (e.g.,
+  // just Bundle.app/).
+  SourceFile GetBundleRootDirOutput(const Settings* settings) const;

[brettw, 2016/04/18 20:16:14]

Can this return a SourceDir instead? The thing you're returning is really a
directory so I think we should be semantically correct here (will need to ensure
it ends in a slash before you construct it).

[Robert Sesek, 2016/04/19 15:37:51]

Is it acceptable to convert a SourceDir to an OutputFile? There isn't a direct
ctor for that so it would have to be indirected through .value() conversion.

Conceptually this may actually be a SourceFile, though. This CL basically
treating the output of a create_bundle as a single unit (a "source file") so
that it can be used as a source elsewhere.

[brettw, 2016/04/21 19:14:00]

I can kind of see that. Can the comment above the function explain what you just
wrote here about why it's a SourceFile?

[Robert Sesek, 2016/04/21 21:03:20]

Done.

+
   // Returns the list of inputs for the compilation of the asset catalog.
   SourceFiles& asset_catalog_sources() { return asset_catalog_sources_; }
   const SourceFiles& asset_catalog_sources() const {