Move StringPiece into the base namespace. It is colliding

base/debug_util_posix.cc

Index: base/debug_util_posix.cc
diff --git a/base/debug_util_posix.cc b/base/debug_util_posix.cc
index dd227100c1f1dab4b7bb8f62482d73bc18cd0731..081f4c480228215bc4e498909f7247228b0390c8 100644
--- a/base/debug_util_posix.cc
+++ b/base/debug_util_posix.cc
@@ -92,11 +92,11 @@ bool DebugUtil::BeingDebugged() {
   if (num_read <= 0)
     return false;
 
-  StringPiece status(buf, num_read);
-  StringPiece tracer("TracerPid:\t");
+  base::StringPiece status(buf, num_read);
+  base::StringPiece tracer("TracerPid:\t");
 
-  StringPiece::size_type pid_index = status.find(tracer);
-  if (pid_index == StringPiece::npos)
+  base::StringPiece::size_type pid_index = status.find(tracer);
+  if (pid_index == base::StringPiece::npos)
     return false;
 
   // Our pid is 0 without a debugger, assume this for any pid starting with 0.