base/threading: restrict to set only current thread priority

base/threading/platform_thread_win.cc

Index: base/threading/platform_thread_win.cc
diff --git a/base/threading/platform_thread_win.cc b/base/threading/platform_thread_win.cc
index 395fc9e20173ad00797c85248584a9d7d1826d7d..520fcd353b2cb1d12e6734ad49635936248b69b3 100644
--- a/base/threading/platform_thread_win.cc
+++ b/base/threading/platform_thread_win.cc
@@ -195,7 +195,7 @@ bool PlatformThread::CreateWithPriority(size_t stack_size, Delegate* delegate,
                                         ThreadPriority priority) {
   bool result = Create(stack_size, delegate, thread_handle);
   if (result)
-    SetThreadPriority(*thread_handle, priority);
+    SetCurrentThreadPriority(priority);

[gab, 2015/06/23 17:01:32]

Hmm, this is incorrect no? This code runs on the thread creating the thread of
interest, not on that thread itself.

I think we may need something like StartWithOptions in the Windows
implementation as well (as a precursor CL).

[Takashi Toyoshima, 2015/06/24 04:15:39]

Oops, thank you for catching this.
Yes, definitely I should fix it in a separate CL.
Thanks!

   return result;
 }
 
@@ -231,10 +231,7 @@ void PlatformThread::Join(PlatformThreadHandle thread_handle) {
 }
 
 // static
-void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
-                                       ThreadPriority priority) {
-  DCHECK(!handle.is_null());
-
+void PlatformThread::SetCurrentThreadPriority(ThreadPriority priority) {
   int desired_priority = THREAD_PRIORITY_ERROR_RETURN;
   switch (priority) {
     case ThreadPriority::BACKGROUND:
@@ -258,16 +255,16 @@ void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
 #ifndef NDEBUG
   const BOOL success =
 #endif
-      ::SetThreadPriority(handle.platform_handle(), desired_priority);
+      ::SetThreadPriority(PlatformThread::CurrentHandle().platform_handle(),
+                          desired_priority);
   DPLOG_IF(ERROR, !success) << "Failed to set thread priority to "
                             << desired_priority;
 }
 
 // static
-ThreadPriority PlatformThread::GetThreadPriority(PlatformThreadHandle handle) {
-  DCHECK(!handle.is_null());
-
-  int priority = ::GetThreadPriority(handle.platform_handle());
+ThreadPriority PlatformThread::GetCurrentThreadPriority() {
+  int priority =
+      ::GetThreadPriority(PlatformThread::CurrentHandle().platform_handle());
   switch (priority) {
     case THREAD_PRIORITY_LOWEST:
       return ThreadPriority::BACKGROUND;