Allow shared modules to whitelist extensions that import them.

extensions/common/manifest_handlers/shared_module_info.h

Index: extensions/common/manifest_handlers/shared_module_info.h
diff --git a/extensions/common/manifest_handlers/shared_module_info.h b/extensions/common/manifest_handlers/shared_module_info.h
index 4240ed7a81778e24e7e31718627d691158facb91..72fd506b21066e13e9a209461779458e705ba4a8 100644
--- a/extensions/common/manifest_handlers/shared_module_info.h
+++ b/extensions/common/manifest_handlers/shared_module_info.h
@@ -36,6 +36,11 @@ class SharedModuleInfo : public Extension::ManifestData {
   static bool IsSharedModule(const Extension* extension);
   static bool IsExportAllowed(const Extension* extension,
                               const std::string& relative_path);
+  // Check against the shared module's whitelist to see if |other_id| can import
+  // its resources. If no whitelist is specified, all extensions can import this
+  // extension.
+  static bool IsExportAllowedByWhitelist(const Extension* extension,
+                                         const std::string& other_id);
 
   // Functions relating to importing resources.
   static bool ImportsExtensionById(const Extension* extension,
@@ -47,6 +52,9 @@ class SharedModuleInfo : public Extension::ManifestData {
   // This extension exports the following resources to other extensions.
   URLPatternSet exported_set_;
 
+  // Optional list of extensions from which importing is allowed.
+  std::set<std::string> export_whitelist_;
+
   // Optional list of module imports of other extensions.
   std::vector<ImportInfo> imports_;
 };