Update OptionGroup::SetValue to take StringRef.

Then deal with all the fallout.

Differential Revision: https://reviews.llvm.org/D24847

llvm-svn: 282265
diff --git a/lldb/source/Commands/CommandObjectExpression.h b/lldb/source/Commands/CommandObjectExpression.h
index 01593ae..7aacc92 100644
--- a/lldb/source/Commands/CommandObjectExpression.h
+++ b/lldb/source/Commands/CommandObjectExpression.h
@@ -34,8 +34,9 @@
 
     llvm::ArrayRef<OptionDefinition> GetDefinitions() override;
 
-    Error SetOptionValue(uint32_t option_idx, const char *option_value,
+    Error SetOptionValue(uint32_t option_idx, llvm::StringRef option_value,
                          ExecutionContext *execution_context) override;
+    Error SetOptionValue(uint32_t, const char *, ExecutionContext *) = delete;
 
     void OptionParsingStarting(ExecutionContext *execution_context) override;