Remove BindStateHolder and have Bind() return a Callback<> object directly.

base/debug/trace_event_unittest.cc

 // Copyright (c) 2011 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 "base/debug/trace_event.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
@@ skipping 24 matching lines @@
   const char* value;
   CompareOp op;
 };
 
 class TraceEventTestFixture : public testing::Test {
  public:
   // This fixture does not use SetUp() because the fixture must be manually set
   // up multiple times when testing AtExit. Use ManualTestSetUp for this.
   void ManualTestSetUp();
   void OnTraceDataCollected(
-      scoped_refptr<TraceLog::RefCountedString> events_str);
+      const scoped_refptr<TraceLog::RefCountedString>& events_str);
   DictionaryValue* FindMatchingTraceEntry(const JsonKeyValue* key_values);
   DictionaryValue* FindNamePhase(const char* name, const char* phase);
   DictionaryValue* FindNamePhaseKeyValue(const char* name,
                                          const char* phase,
                                          const char* key,
                                          const char* value);
   bool FindMatchingValue(const char* key,
                          const char* value);
   bool FindNonMatchingValue(const char* key,
                             const char* value);
@@ skipping 26 matching lines @@
   TraceLog* tracelog = TraceLog::GetInstance();
   ASSERT_TRUE(tracelog);
   ASSERT_FALSE(tracelog->IsEnabled());
   tracelog->SetOutputCallback(
       base::Bind(&TraceEventTestFixture::OnTraceDataCollected,
                  base::Unretained(this)));
   trace_buffer_.SetOutputCallback(json_output_.GetCallback());
 }
 
 void TraceEventTestFixture::OnTraceDataCollected(
-    scoped_refptr<TraceLog::RefCountedString> events_str) {
+    const scoped_refptr<TraceLog::RefCountedString>& events_str) {
   AutoLock lock(lock_);
   json_output_.json_output.clear();
   trace_buffer_.Start();
   trace_buffer_.AddFragment(events_str->data);
   trace_buffer_.Finish();
 
   scoped_ptr<Value> root;
   root.reset(base::JSONReader::Read(json_output_.json_output, false));
 
   ListValue* root_list = NULL;
@@ skipping 1007 matching lines @@
   Clear();
 
   trace_buffer_.Start();
   trace_buffer_.AddFragment("bla1,bla2,bla3,bla4");
   trace_buffer_.Finish();
   EXPECT_STREQ(json_output_.json_output.c_str(), "[bla1,bla2,bla3,bla4]");
 }
 
 }  // namespace debug
 }  // namespace base