tracing: Make ConvertableToTraceFormat move-only scoped_ptr

base/trace_event/trace_event_impl.cc

Index: base/trace_event/trace_event_impl.cc
diff --git a/base/trace_event/trace_event_impl.cc b/base/trace_event/trace_event_impl.cc
index 2ac19623960f57dbf41c02bd0c1eaec8bbd1afcb..c0dc8436fa7ed601f0e065eca913001698c17dc3 100644
--- a/base/trace_event/trace_event_impl.cc
+++ b/base/trace_event/trace_event_impl.cc
@@ -56,27 +56,27 @@ TraceEvent::TraceEvent()
 TraceEvent::~TraceEvent() {
 }
 
-void TraceEvent::CopyFrom(const TraceEvent& other) {
-  timestamp_ = other.timestamp_;
-  thread_timestamp_ = other.thread_timestamp_;
-  duration_ = other.duration_;
-  scope_ = other.scope_;
-  id_ = other.id_;
-  category_group_enabled_ = other.category_group_enabled_;
-  name_ = other.name_;
-  if (other.flags_ & TRACE_EVENT_FLAG_HAS_PROCESS_ID)
-    process_id_ = other.process_id_;
+void TraceEvent::MoveFrom(scoped_ptr<TraceEvent> other) {
+  timestamp_ = other->timestamp_;
+  thread_timestamp_ = other->thread_timestamp_;
+  duration_ = other->duration_;
+  scope_ = other->scope_;
+  id_ = other->id_;
+  category_group_enabled_ = other->category_group_enabled_;
+  name_ = other->name_;
+  if (other->flags_ & TRACE_EVENT_FLAG_HAS_PROCESS_ID)
+    process_id_ = other->process_id_;
   else
-    thread_id_ = other.thread_id_;
-  phase_ = other.phase_;
-  flags_ = other.flags_;
-  parameter_copy_storage_ = other.parameter_copy_storage_;
+    thread_id_ = other->thread_id_;
+  phase_ = other->phase_;
+  flags_ = other->flags_;
+  parameter_copy_storage_ = std::move(other->parameter_copy_storage_);
 
   for (int i = 0; i < kTraceMaxNumArgs; ++i) {
-    arg_names_[i] = other.arg_names_[i];
-    arg_types_[i] = other.arg_types_[i];
-    arg_values_[i] = other.arg_values_[i];
-    convertable_values_[i] = other.convertable_values_[i];
+    arg_names_[i] = other->arg_names_[i];
+    arg_types_[i] = other->arg_types_[i];
+    arg_values_[i] = other->arg_values_[i];
+    convertable_values_[i] = std::move(other->convertable_values_[i]);
   }
 }
 
@@ -94,7 +94,7 @@ void TraceEvent::Initialize(
     const char** arg_names,
     const unsigned char* arg_types,
     const unsigned long long* arg_values,
-    const scoped_refptr<ConvertableToTraceFormat>* convertable_values,
+    scoped_ptr<ConvertableToTraceFormat>* convertable_values,
     unsigned int flags) {
   timestamp_ = timestamp;
   thread_timestamp_ = thread_timestamp;
@@ -115,15 +115,17 @@ void TraceEvent::Initialize(
     arg_names_[i] = arg_names[i];
     arg_types_[i] = arg_types[i];
 
-    if (arg_types[i] == TRACE_VALUE_TYPE_CONVERTABLE)
-      convertable_values_[i] = convertable_values[i];
-    else
+    if (arg_types[i] == TRACE_VALUE_TYPE_CONVERTABLE) {
+      convertable_values_[i] = std::move(convertable_values[i]);
+    } else {
       arg_values_[i].as_uint = arg_values[i];
+      convertable_values_[i].reset();
+    }
   }
   for (; i < kTraceMaxNumArgs; ++i) {
     arg_names_[i] = NULL;
     arg_values_[i].as_uint = 0u;
-    convertable_values_[i] = NULL;
+    convertable_values_[i].reset();
     arg_types_[i] = TRACE_VALUE_TYPE_UINT;
   }
 
@@ -151,9 +153,9 @@ void TraceEvent::Initialize(
   }
 
   if (alloc_size) {
-    parameter_copy_storage_ = new RefCountedString;
-    parameter_copy_storage_->data().resize(alloc_size);
-    char* ptr = string_as_array(&parameter_copy_storage_->data());
+    parameter_copy_storage_.reset(new std::string);
+    parameter_copy_storage_->resize(alloc_size);
+    char* ptr = string_as_array(parameter_copy_storage_.get());
     const char* end = ptr + alloc_size;
     if (copy) {
       CopyTraceEventParameter(&ptr, &name_, end);
@@ -176,9 +178,9 @@ void TraceEvent::Reset() {
   // Only reset fields that won't be initialized in Initialize(), or that may
   // hold references to other objects.
   duration_ = TimeDelta::FromInternalValue(-1);
-  parameter_copy_storage_ = NULL;
+  parameter_copy_storage_.reset();
   for (int i = 0; i < kTraceMaxNumArgs; ++i)
-    convertable_values_[i] = NULL;
+    convertable_values_[i].reset();
 }
 
 void TraceEvent::UpdateDuration(const TimeTicks& now,
@@ -196,11 +198,8 @@ void TraceEvent::EstimateTraceMemoryOverhead(
     TraceEventMemoryOverhead* overhead) {
   overhead->Add("TraceEvent", sizeof(*this));
 
-  // TODO(primiano): parameter_copy_storage_ is refcounted and, in theory,
-  // could be shared by several events and we might overcount. In practice
-  // this is unlikely but it's worth checking.
   if (parameter_copy_storage_)
-    overhead->AddRefCountedString(*parameter_copy_storage_.get());
+    overhead->AddString(*parameter_copy_storage_);
 
   for (size_t i = 0; i < kTraceMaxNumArgs; ++i) {
     if (arg_types_[i] == TRACE_VALUE_TYPE_CONVERTABLE)