Remove Blink's ConvertableToTraceFormat

third_party/WebKit/Source/platform/EventTracer.cpp

Index: third_party/WebKit/Source/platform/EventTracer.cpp
diff --git a/third_party/WebKit/Source/platform/EventTracer.cpp b/third_party/WebKit/Source/platform/EventTracer.cpp
index 4bce3220ac569b75ffc61f608ee19d15a6f0b76d..0e2b0379a103de50eee16db679c619b862f0fb37 100644
--- a/third_party/WebKit/Source/platform/EventTracer.cpp
+++ b/third_party/WebKit/Source/platform/EventTracer.cpp
@@ -32,6 +32,8 @@
 
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
+#include "base/trace_event/trace_event_argument.h"
+#include "platform/TracedValue.h"
 #include "public/platform/Platform.h"
 #include "wtf/Assertions.h"
 #include "wtf/text/StringUTF8Adaptor.h"
@@ -42,37 +44,6 @@ namespace blink {
 static_assert(sizeof(TraceEvent::TraceEventHandle) == sizeof(base::trace_event::TraceEventHandle), "TraceEventHandle types must be the same");
 static_assert(sizeof(TraceEvent::TraceEventAPIAtomicWord) == sizeof(const char*), "TraceEventAPIAtomicWord must be pointer-sized.");
 
-namespace {
-
-class ConvertableToTraceFormatWrapper : public base::trace_event::ConvertableToTraceFormat {
-public:
-    // We move a reference pointer from |convertable| to |m_convertable|,
-    // rather than copying, for thread safety. https://crbug.com/478149
-    explicit ConvertableToTraceFormatWrapper(PassRefPtr<blink::TraceEvent::ConvertableToTraceFormat> convertable)
-        : m_convertable(convertable)
-    {
-        ASSERT(m_convertable);
-    }
-    void AppendAsTraceFormat(std::string* out) const override
-    {
-        // TODO(bashi): Avoid copying.
-        String traceFormat = m_convertable->asTraceFormat();
-        StringUTF8Adaptor utf8(traceFormat);
-        out->append(utf8.data(), utf8.length());
-    }
-    void EstimateTraceMemoryOverhead(base::trace_event::TraceEventMemoryOverhead* overhead)
-    {
-        m_convertable->estimateTraceMemoryOverhead(overhead);
-    }
-
-private:
-    ~ConvertableToTraceFormatWrapper() override {}
-
-    RefPtr<blink::TraceEvent::ConvertableToTraceFormat> m_convertable;
-};
-
-} // namespace
-
 // The dummy variable is needed to avoid a crash when someone updates the state variables
 // before EventTracer::initialize() is called.
 TraceEvent::TraceEventAPIAtomicWord dummyTraceSamplingState = 0;
@@ -101,17 +72,17 @@ TraceEvent::TraceEventHandle EventTracer::addTraceEvent(char phase, const unsign
     const char* name, unsigned long long id, unsigned long long bindId, double timestamp,
     int numArgs, const char* argNames[], const unsigned char argTypes[],
     const unsigned long long argValues[],
-    PassRefPtr<TraceEvent::ConvertableToTraceFormat> convertableValue1,
-    PassRefPtr<TraceEvent::ConvertableToTraceFormat> convertableValue2,
+    PassRefPtr<TracedValue> convertableValue1,
+    PassRefPtr<TracedValue> convertableValue2,
     unsigned flags)
 {
-    scoped_refptr<base::trace_event::ConvertableToTraceFormat> wrappers[2];
+    scoped_refptr<base::trace_event::ConvertableToTraceFormat> convertables[2];
     ASSERT(numArgs <= 2);
     if (numArgs >= 1 && argTypes[0] == TRACE_VALUE_TYPE_CONVERTABLE)
-        wrappers[0] = new ConvertableToTraceFormatWrapper(convertableValue1);
+        convertables[0] = convertableValue1->m_tracedValue;

[hiroshige, 2016/01/28 12:05:01]

Probably we have to move the scoped_ptr from |convertableValue1->m_tracedValue|
to |convertables[0]|, so that |convertableValue1->m_tracedValue| becomes null
after this line for thread safety,
as ConvertableToTraceFormatWrapper() did similar things.
(See comments in L49-50 in ConvertableToTraceFormatWrapper)

[bashi, 2016/01/29 02:25:26]

Good catch! Done.

     if (numArgs >= 2 && argTypes[1] == TRACE_VALUE_TYPE_CONVERTABLE)
-        wrappers[1] = new ConvertableToTraceFormatWrapper(convertableValue2);
-    return addTraceEvent(phase, categoryEnabledFlag, name, id, bindId, timestamp, numArgs, argNames, argTypes, argValues, wrappers, flags);
+        convertables[1] = convertableValue2->m_tracedValue;

[hiroshige, 2016/01/28 12:05:01]

ditto.

+    return addTraceEvent(phase, categoryEnabledFlag, name, id, bindId, timestamp, numArgs, argNames, argTypes, argValues, convertables, flags);
 }
 
 TraceEvent::TraceEventHandle EventTracer::addTraceEvent(char phase, const unsigned char* categoryEnabledFlag,