liblp: change some functions to use string_view

Converting all of them to string_view requires some
non-trivial amount of refactoring (because there is not
an implicit conversion from string_view to string), and
hence may be done later if necessary.

Test: builds
Bug: 135752105
Change-Id: I936ae7117500fadc7b34a5b91b279bc863d9919d
diff --git a/fs_mgr/liblp/builder.cpp b/fs_mgr/liblp/builder.cpp
index 777743c..33ea8c5 100644
--- a/fs_mgr/liblp/builder.cpp
+++ b/fs_mgr/liblp/builder.cpp
@@ -458,7 +458,7 @@
     return nullptr;
 }
 
-PartitionGroup* MetadataBuilder::FindGroup(const std::string& group_name) {
+PartitionGroup* MetadataBuilder::FindGroup(std::string_view group_name) {
     for (const auto& group : groups_) {
         if (group->name() == group_name) {
             return group.get();
@@ -1083,7 +1083,7 @@
     return partitions;
 }
 
-bool MetadataBuilder::ChangePartitionGroup(Partition* partition, const std::string& group_name) {
+bool MetadataBuilder::ChangePartitionGroup(Partition* partition, std::string_view group_name) {
     if (!FindGroup(group_name)) {
         LERROR << "Partition cannot change to unknown group: " << group_name;
         return false;
diff --git a/fs_mgr/liblp/include/liblp/builder.h b/fs_mgr/liblp/include/liblp/builder.h
index 3b229bd..d2a206b 100644
--- a/fs_mgr/liblp/include/liblp/builder.h
+++ b/fs_mgr/liblp/include/liblp/builder.h
@@ -128,7 +128,7 @@
 
   private:
     void ShrinkTo(uint64_t aligned_size);
-    void set_group_name(const std::string& group_name) { group_name_ = group_name; }
+    void set_group_name(std::string_view group_name) { group_name_ = group_name; }
 
     std::string name_;
     std::string group_name_;
@@ -227,7 +227,7 @@
     Partition* FindPartition(const std::string& name);
 
     // Find a group by name. If no group is found, nullptr is returned.
-    PartitionGroup* FindGroup(const std::string& name);
+    PartitionGroup* FindGroup(std::string_view name);
 
     // Add a predetermined extent to a partition.
     bool AddLinearExtent(Partition* partition, const std::string& block_device,
@@ -252,7 +252,7 @@
     // the metadata is exported, to avoid errors during potential group and
     // size shuffling operations. This will return false if the new group does
     // not exist.
-    bool ChangePartitionGroup(Partition* partition, const std::string& group_name);
+    bool ChangePartitionGroup(Partition* partition, std::string_view group_name);
 
     // Changes the size of a partition group. Size constraints will not be
     // checked until metadata is exported, to avoid errors during group