Clone for AggregateHeapProfileInfo

Summary: Following diff D38518063 makes it public, users may want to clone it.

Reviewed By: krallin

Differential Revision: D38527562

fbshipit-source-id: 6f26b846cb718ced7a30619be51eef78d3d46f4c

Author: stepancheg

starlark/src/values/layout/heap/profile/aggregated.rs

@@ -196,6 +196,7 @@ impl<'v> ArenaVisitor<'v> for StackCollector {
 }
 
 /// Aggregated stack frame data.
+#[derive(Clone)]
 pub(crate) struct StackFrame {
     /// Aggregated callees.
     pub(crate) callees: SmallMap<StringId, StackFrame>,
@@ -285,6 +286,7 @@ impl<'c> StackFrameWithContext<'c> {
     }
 }
 
+#[derive(Clone)]
 pub(crate) struct AggregateHeapProfileInfo {
     pub(crate) strings: StringIndex,
     pub(crate) root: StackFrame,

starlark/src/values/layout/heap/profile/string_index.rs

@@ -20,7 +20,7 @@ use gazebo::prelude::*;
 use starlark_map::small_set::SmallSet;
 
 /// Map strings to integers 0, 1, 2, ...
-#[derive(Default)]
+#[derive(Default, Clone)]
 pub(crate) struct StringIndex {
     strings: SmallSet<String>,
 }