Base: Don't overwrite the thread id when ThreadMain exits. There's

no need to do that, and it makes debugging easier to have the value.

Change the logic of IsRunning() to use a dedicated member variable 
instead of overloading the thread id. 

BUG=127931
TEST=none
Review URL: https://chromiumcodereview.appspot.com/10399097

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@138119 0039d316-1c4b-4281-b951-d872f2087c98

base/threading/thread.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -47,6 +47,7 @@ struct Thread::StartupData {
 Thread::Thread(const char* name)
     : started_(false),
       stopping_(false),
+      running_(false),
       startup_data_(NULL),
       thread_(0),
       message_loop_(NULL),
@@ -124,6 +125,10 @@ void Thread::StopSoon() {
   message_loop_->PostTask(FROM_HERE, base::Bind(&ThreadQuitHelper));
 }
 
+bool Thread::IsRunning() const {
+  return running_;
+}
+
 void Thread::Run(MessageLoop* message_loop) {
   message_loop->Run();
 }
@@ -160,7 +165,9 @@ void Thread::ThreadMain() {
     // startup_data_ can't be touched anymore since the starting thread is now
     // unlocked.
 
+    running_ = true;
     Run(message_loop_);
+    running_ = false;
 
     // Let the thread do extra cleanup.
     CleanUp();
@@ -171,7 +178,6 @@ void Thread::ThreadMain() {
     // We can't receive messages anymore.
     message_loop_ = NULL;
   }
-  thread_id_ = kInvalidThreadId;
 }
 
 }  // namespace base

base/threading/thread.h

@@ -131,8 +131,7 @@ class BASE_EXPORT Thread : PlatformThread::Delegate {
   PlatformThreadId thread_id() const { return thread_id_; }
 
   // Returns true if the thread has been started, and not yet stopped.
-  // When a thread is running, |thread_id_| is a valid id.
-  bool IsRunning() const { return thread_id_ != kInvalidThreadId; }
+  bool IsRunning() const;
 
  protected:
   // Called just prior to starting the message loop
@@ -164,6 +163,9 @@ class BASE_EXPORT Thread : PlatformThread::Delegate {
   // |message_loop_|. It may non-NULL and invalid.
   bool stopping_;
 
+  // True while inside of Run().
+  bool running_;
+
   // Used to pass data to ThreadMain.
   struct StartupData;
   StartupData* startup_data_;