Deprecated default FName operator < and >

We've had several cases where the previously default alphabetical sorting caused performance issues when it wasn't needed. We now require you to explicitly choose either slow alphabetical sorting or fast non-alphabetical order.

The fast order does not decode, access or compare actual string data, but the order is not stable between process runs.

#rb steve.robb

[CL 5915265 by Johan Torp in Dev-Core branch]

Engine/Source/Developer/Profiler/Private/Widgets/SEventGraph.cpp

@@ -1051,7 +1051,7 @@ void SEventGraph::FillThreadFilterOptions()
 	// Sort the thread names alphabetically
 	ThreadNamesForCombo.Sort([]( const TSharedPtr<FName> Lhs, const TSharedPtr<FName> Rhs ) 
 	{
-		return Lhs->IsNone() || ( !Rhs->IsNone() && *Lhs < *Rhs );
+		return Lhs->IsNone() || ( !Rhs->IsNone() && Lhs->LexicalLess(*Rhs) );
 	});
 
 	// Refresh the combo box

Engine/Source/Developer/Profiler/Private/Widgets/SFiltersAndPresets.h

@@ -241,7 +241,7 @@ struct FGroupAndStatSorting
 	{
 		FORCEINLINE_DEBUGGABLE bool operator()( const FGroupOrStatNodePtr& A, const FGroupOrStatNodePtr& B ) const 
 		{
-			return A->GetName() < B->GetName();
+			return A->GetName().LexicalLess(B->GetName());
 		}
 	};
 
@@ -250,7 +250,7 @@ struct FGroupAndStatSorting
 	{
 		FORCEINLINE_DEBUGGABLE bool operator()( const FGroupOrStatNodePtr& A, const FGroupOrStatNodePtr& B ) const 
 		{
-			return A->GetGroupName() < B->GetGroupName();
+			return A->GetGroupName().LexicalLess(B->GetGroupName());
 		}
 	};
 
@@ -265,7 +265,7 @@ struct FGroupAndStatSorting
 			if( TypeA == TypeB )
 			{
 				// Sort by stat name.
-				return A->GetName() < B->GetName();
+				return A->GetName().LexicalLess(B->GetName());
 			}
 			else
 			{