Deleted OS_WIN and all Windows specific files from base.

base/threading/platform_thread.h

Index: base/threading/platform_thread.h
diff --git a/base/threading/platform_thread.h b/base/threading/platform_thread.h
index 3468f45f91efd4929ea838f91559251a2d75a4ef..7914c92669ac1dcb8fdbd5cbd385cdbcf0ed315a 100644
--- a/base/threading/platform_thread.h
+++ b/base/threading/platform_thread.h
@@ -14,9 +14,7 @@
 #include "base/time/time.h"
 #include "build/build_config.h"
 
-#if defined(OS_WIN)
-#include <windows.h>
-#elif defined(OS_POSIX)
+#if defined(OS_POSIX)
 #include <pthread.h>
 #include <unistd.h>
 #endif
@@ -24,9 +22,7 @@
 namespace base {
 
 // Used for logging. Always an integer value.
-#if defined(OS_WIN)
-typedef DWORD PlatformThreadId;
-#elif defined(OS_POSIX)
+#if defined(OS_POSIX)
 typedef pid_t PlatformThreadId;
 #endif
 
@@ -40,9 +36,7 @@ typedef pid_t PlatformThreadId;
 // to distinguish a new thread from an old, dead thread.
 class PlatformThreadRef {
  public:
-#if defined(OS_WIN)
-  typedef DWORD RefType;
-#elif defined(OS_POSIX)
+#if defined(OS_POSIX)
   typedef pthread_t RefType;
 #endif
   PlatformThreadRef()
@@ -67,9 +61,7 @@ class PlatformThreadRef {
 // Used to operate on threads.
 class PlatformThreadHandle {
  public:
-#if defined(OS_WIN)
-  typedef void* Handle;
-#elif defined(OS_POSIX)
+#if defined(OS_POSIX)
   typedef pthread_t Handle;
 #endif