Suppress unitialized use of memory for random_number_ seed

base/tracked_objects.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/tracked_objects.h"
 
 #include <math.h>
 
 #include "base/format_macros.h"
 #include "base/message_loop.h"
 #include "base/stringprintf.h"
+#include "base/third_party/valgrind/memcheck.h"
 #include "base/threading/thread_restrictions.h"
 #include "build/build_config.h"
 #include "base/port.h"
 
 using base::TimeDelta;
 
 namespace tracked_objects {
 
 namespace {
 // Flag to compile out almost all of the task tracking code.
@@ skipping 189 matching lines @@
       next_retired_worker_(NULL),
       worker_thread_number_(thread_number) {
   CHECK_GT(thread_number, 0);
   base::StringAppendF(&thread_name_, "WorkerThread-%d", thread_number);
   PushToHeadOfList();  // Which sets real incarnation_count_for_pool_.
 }
 
 ThreadData::~ThreadData() {}
 
 void ThreadData::PushToHeadOfList() {
+  VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE(&random_number_,
+                                           sizeof(random_number_));
   // Toss in a hint of randomness (atop the uniniitalized value).
   random_number_ += static_cast<int32>(this - static_cast<ThreadData*>(0));
   random_number_ ^= (Now() - TrackedTime()).InMilliseconds();
 
   DCHECK(!next_);
   base::AutoLock lock(*list_lock_.Pointer());
   incarnation_count_for_pool_ = incarnation_counter_;
   next_ = all_thread_data_list_head_;
   all_thread_data_list_head_ = this;
 }
@@ skipping 508 matching lines @@
 
 base::ListValue* DataCollector::ToValue() const {
   base::ListValue* list = new base::ListValue;
   for (size_t i = 0; i < collection_.size(); ++i) {
     list->Append(collection_[i].ToValue());
   }
   return list;
 }
 
 }  // namespace tracked_objects