Revert of Adding StringPiece read/write support to pickle.

ipc/ipc_perftest_support.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ipc/ipc_perftest_support.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 85 matching lines @@
   }
 
   bool OnMessageReceived(const Message& message) override {
     CHECK(channel_);
 
     PickleIterator iter(message);
     int64 time_internal;
     EXPECT_TRUE(iter.ReadInt64(&time_internal));
     int msgid;
     EXPECT_TRUE(iter.ReadInt(&msgid));
-    base::StringPiece payload;
-    EXPECT_TRUE(iter.ReadStringPiece(&payload));
+    std::string payload;
+    EXPECT_TRUE(iter.ReadString(&payload));
 
     // Include message deserialization in latency.
     base::TimeTicks now = base::TimeTicks::Now();
 
     if (payload == "hello") {
       latency_tracker_.Reset();
     } else if (payload == "quit") {
       latency_tracker_.ShowResults();
       base::MessageLoop::current()->QuitWhenIdle();
       return true;
@@ skipping 254 matching lines @@
   auto set_result = SetThreadAffinityMask(GetCurrentThread(), old_affinity_);
   DCHECK_NE(0u, set_result);
 #elif defined(OS_LINUX)
   auto set_result = sched_setaffinity(0, sizeof(old_cpuset_), &old_cpuset_);
   DCHECK_EQ(0, set_result);
 #endif
 }
 
 }  // namespace test
 }  // namespace IPC