Added support to trace_event for passing static string arguments without copy

base/debug/trace_event.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 <algorithm>
 
 #if defined(OS_WIN)
 #include "base/debug/trace_event_win.h"
@@ skipping 65 matching lines @@
       *out += temp_string;
       break;
     case TRACE_TYPE_POINTER:
       base::snprintf(temp_string, arraysize(temp_string), "%llu",
                      static_cast<unsigned long long>(
                        reinterpret_cast<intptr_t>(
                          as_pointer())));
       *out += temp_string;
       break;
     case TRACE_TYPE_STRING:
+    case TRACE_TYPE_STATIC_STRING:
       *out += "\"";
       start_pos = out->size();
       *out += as_string();
       // replace " character with '
       while ((start_pos = out->find_first_of('\"', start_pos)) !=
              std::string::npos)
         (*out)[start_pos] = '\'';
       *out += "\"";
       break;
     default:
@@ skipping 77 matching lines @@
   size_t alloc_size = 0;
   if (copy) {
     alloc_size += GetAllocLength(name);
     alloc_size += GetAllocLength(arg1_name);
     alloc_size += GetAllocLength(arg2_name);
   }
   // We always take a copy of string arg_vals, even if |copy| was not set.
   if (arg1_val.type() == TraceValue::TRACE_TYPE_STRING)
     alloc_size += GetAllocLength(arg1_val.as_string());
   if (arg2_val.type() == TraceValue::TRACE_TYPE_STRING)
     alloc_size += GetAllocLength(arg2_val.as_string());

[Evan Martin, 2011/08/29 22:57:34]

For others confused by this CL, this here is the important logic that
distinguishes TYPE_STRING from TYPE_STATIC_STRING.

 
   if (alloc_size) {
     parameter_copy_storage_ = new base::RefCountedString;
     parameter_copy_storage_->data().resize(alloc_size);
     char* ptr = string_as_array(&parameter_copy_storage_->data());
     const char* end = ptr + alloc_size;
     if (copy) {
       CopyTraceEventParameter(&ptr, &name_, end);
       CopyTraceEventParameter(&ptr, &arg_names_[0], end);
       CopyTraceEventParameter(&ptr, &arg_names_[1], end);
@@ skipping 331 matching lines @@
         p_data_->name,
         NULL, 0, NULL, 0,
         p_data_->threshold_begin_id, p_data_->threshold, false);
   }
 }
 
 } // namespace internal
 
 }  // namespace debug
 }  // namespace base