[NTP Snippets] Introduce ContentSuggestion::ID

components/ntp_snippets/category_factory.cc

Index: components/ntp_snippets/category_factory.cc
diff --git a/components/ntp_snippets/category_factory.cc b/components/ntp_snippets/category_factory.cc
index 9962f0771eb05fda3eb43074cfb66ccbf5b85e2e..4da984e016232a02443f6d041209e40c429b63c2 100644
--- a/components/ntp_snippets/category_factory.cc
+++ b/components/ntp_snippets/category_factory.cc
@@ -12,13 +12,6 @@
 
 namespace ntp_snippets {
 
-namespace {
-
-const char kCombinedIDFormat[] = "%d|%s";
-const char kSeparator = '|';
-
-}  // namespace
-
 CategoryFactory::CategoryFactory() {
   // Add all local categories in a fixed order.
   AddKnownCategory(KnownCategories::DOWNLOADS);
@@ -66,32 +59,6 @@ bool CategoryFactory::CompareCategories(const Category& left,
                                      ordered_categories_.end(), right);
 }
 
-std::string CategoryFactory::MakeUniqueID(
-    Category category,
-    const std::string& within_category_id) const {
-  return base::StringPrintf(kCombinedIDFormat, category.id(),
-                            within_category_id.c_str());
-}
-
-Category CategoryFactory::GetCategoryFromUniqueID(
-    const std::string& unique_id) {
-  size_t colon_index = unique_id.find(kSeparator);
-  DCHECK_NE(std::string::npos, colon_index) << "Not a valid unique_id: "
-                                            << unique_id;
-  int category = -1;
-  bool ret = base::StringToInt(unique_id.substr(0, colon_index), &category);
-  DCHECK(ret) << "Non-numeric category part in unique_id: " << unique_id;
-  return FromIDValue(category);
-}
-
-std::string CategoryFactory::GetWithinCategoryIDFromUniqueID(
-    const std::string& unique_id) const {
-  size_t colon_index = unique_id.find(kSeparator);
-  DCHECK_NE(std::string::npos, colon_index) << "Not a valid unique_id: "
-                                            << unique_id;
-  return unique_id.substr(colon_index + 1);
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // Private methods