PlatformThreadHandle: remove public id() interface

base/threading/thread.h

Index: base/threading/thread.h
diff --git a/base/threading/thread.h b/base/threading/thread.h
index 5126491b3861cdb60f23eec1b40b11466d27a33a..cc62abf284769ff74c47f445a4bb87d072f09864 100644
--- a/base/threading/thread.h
+++ b/base/threading/thread.h
@@ -171,7 +171,7 @@ class BASE_EXPORT Thread : PlatformThread::Delegate {
   PlatformThreadHandle thread_handle() { return thread_; }
 
   // The thread ID.

[gab, 2015/07/02 12:00:52]

// The thread ID. Only valid after this Thread was launched.

[Takashi Toyoshima, 2015/07/03 04:22:56]

Ah, that's the thing I should explain here.
By the way, I think we use "start" here and there instead of "launch", so if you
do not have a special meaning on "launch", I prefer "start". WDYT?

[gab, 2015/07/08 18:35:20]

"Started" SGTM.

-  PlatformThreadId thread_id() const;
+  PlatformThreadId thread_id() const { return id_; }
 
   // Returns true if the thread has been started, and not yet stopped.
   bool IsRunning() const;
@@ -216,11 +216,15 @@ class BASE_EXPORT Thread : PlatformThread::Delegate {
 
   // True while inside of Run().
   bool running_;
-  mutable base::Lock running_lock_;  // Protects running_.
+  mutable base::Lock running_lock_;  // Protects |running_|.
 
   // The thread's handle.
   PlatformThreadHandle thread_;
-  mutable base::Lock thread_lock_;  // Protects thread_.
+
+  // The thread's id.

[gab, 2015/07/02 12:00:52]

// The thread's id once it was started.

[Takashi Toyoshima, 2015/07/03 04:22:56]

Done.

+  PlatformThreadId id_;
+
+  mutable base::Lock thread_lock_;  // Protects |thread_| and |id_|.

[Takashi Toyoshima, 2015/07/03 04:22:56]

Oops, I only updated the comment, but did nothing for protecting id_ :(

 
   // The thread's message loop.  Valid only while the thread is alive.  Set
   // by the created thread.