Adding StringPiece read/write support to pickle.

ipc/ipc_perftest_support.cc

Index: ipc/ipc_perftest_support.cc
diff --git a/ipc/ipc_perftest_support.cc b/ipc/ipc_perftest_support.cc
index f8a11c549dc8387aebc3e89ecd26ef3628a0f0c6..714410348ee0227de9ddebed3ea7d999dbc99f2d 100644
--- a/ipc/ipc_perftest_support.cc
+++ b/ipc/ipc_perftest_support.cc
@@ -103,8 +103,8 @@ class ChannelReflectorListener : public Listener {
     EXPECT_TRUE(iter.ReadInt64(&time_internal));
     int msgid;
     EXPECT_TRUE(iter.ReadInt(&msgid));
-    std::string payload;
-    EXPECT_TRUE(iter.ReadString(&payload));
+    base::StringPiece payload;
+    EXPECT_TRUE(iter.ReadStringPiece(&payload));
 
     // Include message deserialization in latency.
     base::TimeTicks now = base::TimeTicks::Now();