Moving platform tracing things into platform/tracing.

third_party/WebKit/Source/platform/TracedValue.h

-// Copyright 2014 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.
-
-#ifndef TracedValue_h
-#define TracedValue_h
-
-#include "base/trace_event/trace_event_argument.h"
-#include "platform/PlatformExport.h"
-#include "wtf/text/WTFString.h"
-
-namespace blink {
-
-// TracedValue copies all passed names and values and doesn't retain references.
-class PLATFORM_EXPORT TracedValue final
-    : public base::trace_event::ConvertableToTraceFormat {
-  WTF_MAKE_NONCOPYABLE(TracedValue);
-
- public:
-  ~TracedValue();
-
-  static std::unique_ptr<TracedValue> create();
-
-  void endDictionary();
-  void endArray();
-
-  void setInteger(const char* name, int value);
-  void setDouble(const char* name, double);
-  void setBoolean(const char* name, bool value);
-  void setString(const char* name, const String& value);
-  void beginArray(const char* name);
-  void beginDictionary(const char* name);
-
-  void pushInteger(int);
-  void pushDouble(double);
-  void pushBoolean(bool);
-  void pushString(const String&);
-  void beginArray();
-  void beginDictionary();
-
-  String toString() const;
-
- private:
-  TracedValue();
-
-  // ConvertableToTraceFormat
-
-  // Hide this method from blink code.
-  using base::trace_event::ConvertableToTraceFormat::ToString;
-  void AppendAsTraceFormat(std::string*) const final;
-  void EstimateTraceMemoryOverhead(
-      base::trace_event::TraceEventMemoryOverhead*) final;
-
-  base::trace_event::TracedValue m_tracedValue;
-};
-
-}  // namespace blink
-
-#endif  // TracedValue_h