Remove remaining legacy SplitString calls.

win8/delegate_execute/delegate_execute_operation.cc

Index: win8/delegate_execute/delegate_execute_operation.cc
diff --git a/win8/delegate_execute/delegate_execute_operation.cc b/win8/delegate_execute/delegate_execute_operation.cc
index 277b74b407b87a93d80cad9959dd265e9fdf9259..ce64680b7963ae531744c13bd362e74518123fd1 100644
--- a/win8/delegate_execute/delegate_execute_operation.cc
+++ b/win8/delegate_execute/delegate_execute_operation.cc
@@ -52,8 +52,8 @@ bool DelegateExecuteOperation::Init(const base::CommandLine* cmd_line) {
 }
 
 base::Process DelegateExecuteOperation::GetParent() const {
-  std::vector<base::string16> parts;
-  base::SplitString(mutex_, L'.', &parts);
+  std::vector<base::StringPiece16> parts = base::SplitStringPiece(
+      mutex_, L".", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
   if (parts.size() != 3)
     return base::Process();
   DWORD pid;