ash: Rename AppLaunchId to ShelfID.

ash/public/cpp/shelf_types.cc

Index: ash/public/cpp/shelf_types.cc
diff --git a/ash/public/cpp/shelf_types.cc b/ash/public/cpp/shelf_types.cc
index a4cb0fd44fd23a19918f47c12e9868625cd41a02..53d683239caf45fcfd8a4f7b5dce63ff02048523 100644
--- a/ash/public/cpp/shelf_types.cc
+++ b/ash/public/cpp/shelf_types.cc
@@ -4,6 +4,8 @@
 
 #include "ash/public/cpp/shelf_types.h"
 
+#include "base/logging.h"
+
 namespace ash {
 
 bool IsValidShelfItemType(int64_t type) {
@@ -12,4 +14,34 @@ bool IsValidShelfItemType(int64_t type) {
          type == TYPE_APP || type == TYPE_DIALOG || type == TYPE_UNDEFINED;
 }
 
+ShelfID::ShelfID(const std::string& app_id, const std::string& launch_id)
+    : app_id(app_id), launch_id(launch_id) {
+  DCHECK(launch_id.empty() || !app_id.empty()) << "launch ids require app ids.";
+}
+
+ShelfID::~ShelfID() = default;
+
+ShelfID::ShelfID(const ShelfID& other) = default;
+
+ShelfID::ShelfID(ShelfID&& other) = default;
+
+ShelfID& ShelfID::operator=(const ShelfID& other) = default;
+
+bool ShelfID::operator==(const ShelfID& other) const {
+  return app_id == other.app_id && launch_id == other.launch_id;
+}
+
+bool ShelfID::operator!=(const ShelfID& other) const {
+  return !(*this == other);
+}
+
+bool ShelfID::operator<(const ShelfID& other) const {
+  return app_id < other.app_id ||
+         (app_id == other.app_id && launch_id < other.launch_id);
+}
+
+bool ShelfID::IsNull() const {
+  return app_id.empty() && launch_id.empty();
+}
+
 }  // namespace ash