[lldb/Utility] Make StructuredData::Dictionary::GetKeys return an Array

This patch changes `StructuredData::Dictionary::GetKeys` return type
from an `StructuredData::ObjectSP` to a `StructuredData::ArraySP`.

The function already stored the keys in an array but implicitely upcasted
it to an `ObjectSP`, which required the user to convert it again to a
Array object to access each element.

Since we know the keys should be held by an iterable container, it makes
more sense to return the allocated ArraySP as-is.

Differential Revision: https://reviews.llvm.org/D122426

Signed-off-by: Med Ismail Bennani <[email protected]>

Author: medismailben

lldb/include/lldb/Utility/StructuredData.h

@@ -376,15 +376,15 @@ class StructuredData {
       }
     }
 
-    ObjectSP GetKeys() const {
-      auto object_sp = std::make_shared<Array>();
+    ArraySP GetKeys() const {
+      auto array_sp = std::make_shared<Array>();
       collection::const_iterator iter;
       for (iter = m_dict.begin(); iter != m_dict.end(); ++iter) {
         auto key_object_sp = std::make_shared<String>();
         key_object_sp->SetValue(iter->first.AsCString());
-        object_sp->Push(key_object_sp);
+        array_sp->Push(key_object_sp);
       }
-      return object_sp;
+      return array_sp;
     }
 
     ObjectSP GetValueForKey(llvm::StringRef key) const {