Add full SetThreadPriority support to Windows.

base/threading/platform_thread_internal_posix.h

Index: base/threading/platform_thread_internal_posix.h
diff --git a/base/threading/platform_thread_internal_posix.h b/base/threading/platform_thread_internal_posix.h
index 1ae968fff087d0452af7f36c9a328027a26164b4..4c0705b8be204b57bcd92b9a525eb520850b52aa 100644
--- a/base/threading/platform_thread_internal_posix.h
+++ b/base/threading/platform_thread_internal_posix.h
@@ -21,6 +21,10 @@ extern const ThreadPriorityToNiceValuePair kThreadPriorityToNiceValueMap[4];
 // implementation of kThreadPriorityToNiceValueMap.
 int ThreadPriorityToNiceValue(ThreadPriority priority);
 
+// Returns the ThreadPrioirty matching |nice_value| based on the platform-
+// specific implementation of kThreadPriorityToNiceValueMap.
+ThreadPriority NiceValueToThreadPriority(int nice_value);
+
 // Allows platform specific tweaks to the generic POSIX solution for
 // SetThreadPriority. Returns true if the platform-specific implementation
 // handled this |priority| change, false if the generic implementation should
@@ -28,6 +32,13 @@ int ThreadPriorityToNiceValue(ThreadPriority priority);
 bool HandleSetThreadPriorityForPlatform(PlatformThreadHandle handle,
                                         ThreadPriority priority);
 
+// Mirrors HandleSetThreadPriorityForPlatform(). Returns true if there is a

[rvargas (doing something else), 2015/03/19 22:19:21]

I think we should remove the first sentence. Just document what the fn does.

[gab, 2015/03/30 20:14:45]

Done.

+// platform-specific ThreadPriority set on |handle| (and returns the actual
+// ThreadPriority via |priority|). Returns false otherwise, leaving |priority|
+// untouched.
+bool HandleGetThreadPriorityForPlatform(PlatformThreadHandle handle,

[rvargas (doing something else), 2015/03/19 22:19:21]

I know I just said that this was ok, but reading this CL the HandleXX is
confusing (because we also receive a handle as argument). I think we should
remove that prefix and have Set/GetThreadPriorityForPlatform()

[gab, 2015/03/30 20:14:45]

Done.

+                                        ThreadPriority* priority);
+
 }  // namespace internal
 
 }  // namespace base