Revert 201202 "base: Support setting thread priorities generically."

Broke "sizes" by adding may static initializers.

> base: Support setting thread priorities generically.
> 
> This patch supports setting priorities across platforms
> at the PlatformThread level, by stashing thread id into the
> thread handle on linux/android.
> 
> Since this adds more platform specific code, and #ifdefs
> were starting to get unwieldy, all platform specific code
> is moved into _platform.cc files, with the exception of the
> 'default' implementation, which stay in _posix.
> 
> BUG=170549
> 
> Review URL: https://chromiumcodereview.appspot.com/12741012

TBR=epenner@chromium.org

Review URL: https://codereview.chromium.org/15311004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@201215 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 163 insertions, 397 deletions

diff --git a/base/threading/platform_thread.h b/base/threading/platform_thread.h
index 17e296e..576695a 100644
--- a/base/threading/platform_thread.h
+++ b/base/threading/platform_thread.h
@@ -23,68 +23,27 @@
 
 namespace base {
 
+// PlatformThreadHandle should not be assumed to be a numeric type, since the
+// standard intends to allow pthread_t to be a structure.  This means you
+// should not initialize it to a value, like 0.  If it's a member variable, the
+// constructor can safely "value initialize" using () in the initializer list.
 #if defined(OS_WIN)
 typedef DWORD PlatformThreadId;
+typedef void* PlatformThreadHandle;  // HANDLE
+const PlatformThreadHandle kNullThreadHandle = NULL;
 #elif defined(OS_POSIX)
+typedef pthread_t PlatformThreadHandle;
+const PlatformThreadHandle kNullThreadHandle = 0;
 typedef pid_t PlatformThreadId;
 #endif
 
-class PlatformThreadHandle {
- public:
-#if defined(OS_WIN)
-  typedef void* Handle;
-#elif defined(OS_POSIX)
-  typedef pthread_t Handle;
-#endif
-
-  PlatformThreadHandle()
-      : handle_(0),
-        id_(0) {
-  }
-
-  explicit PlatformThreadHandle(Handle handle)
-      : handle_(handle),
-        id_(0) {
-  }
-
-  PlatformThreadHandle(Handle handle,
-                       PlatformThreadId id)
-      : handle_(handle),
-        id_(id) {
-  }
-
-  bool is_equal(const PlatformThreadHandle& other) {
-    return handle_ == other.handle_;
-  }
-
-  bool is_null() {
-    return !handle_;
-  }
-
-  Handle platform_handle() {
-    return handle_;
-  }
-
- private:
-  friend class PlatformThread;
-
-  Handle handle_;
-  PlatformThreadId id_;
-};
-
-const PlatformThreadHandle kNullThreadHandle(0);
-const PlatformThreadId kInvalidThreadId(0);
-
+const PlatformThreadId kInvalidThreadId = 0;
 
 // Valid values for SetThreadPriority()
 enum ThreadPriority{
   kThreadPriority_Normal,
   // Suitable for low-latency, glitch-resistant audio.
-  kThreadPriority_RealtimeAudio,
-  // Suitable for threads which generate data for the display (at ~60Hz).
-  kThreadPriority_Display,
-  // Suitable for threads that shouldn't disrupt high priority work.
-  kThreadPriority_Background
+  kThreadPriority_RealtimeAudio
 };
 
 // A namespace for low-level thread functions.
@@ -103,9 +62,6 @@ class BASE_EXPORT PlatformThread {
   // Gets the current thread id, which may be useful for logging purposes.
   static PlatformThreadId CurrentId();
 
-  // Get the current handle.
-  static PlatformThreadHandle CurrentHandle();
-
   // Yield the current thread so another thread can be scheduled.
   static void YieldCurrentThread();
 
@@ -150,6 +106,8 @@ class BASE_EXPORT PlatformThread {
   // |thread_handle|.
   static void Join(PlatformThreadHandle thread_handle);
 
+  // Sets the priority of the thread specified in |handle| to |priority|.
+  // This does not work on Linux, use CreateWithPriority() instead.
   static void SetThreadPriority(PlatformThreadHandle handle,
                                 ThreadPriority priority);
 
diff --git a/base/threading/platform_thread_android.cc b/base/threading/platform_thread_android.cc
deleted file mode 100644
index 2802635..0000000
--- a/base/threading/platform_thread_android.cc
+++ /dev/null
@@ -1,105 +0,0 @@
-// 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.
-
-#include "base/threading/platform_thread.h"
-
-#include <errno.h>
-#include <sys/resource.h>
-
-#include "base/android/jni_android.h"
-#include "base/android/thread_utils.h"
-#include "base/lazy_instance.h"
-#include "base/logging.h"
-#include "base/threading/thread_id_name_manager.h"
-#include "base/tracked_objects.h"
-#include "jni/ThreadUtils_jni.h"
-
-namespace base {
-
-namespace {
-int ThreadNiceValue(ThreadPriority priority) {
-  // These nice values are taken from Android, which uses nice
-  // values like linux, but defines some preset nice values.
-  //   Process.THREAD_PRIORITY_AUDIO = -16
-  //   Process.THREAD_PRIORITY_BACKGROUND = 10
-  //   Process.THREAD_PRIORITY_DEFAULT = 0;
-  //   Process.THREAD_PRIORITY_DISPLAY = -4;
-  //   Process.THREAD_PRIORITY_FOREGROUND = -2;
-  //   Process.THREAD_PRIORITY_LESS_FAVORABLE = 1;
-  //   Process.THREAD_PRIORITY_LOWEST = 19;
-  //   Process.THREAD_PRIORITY_MORE_FAVORABLE = -1;
-  //   Process.THREAD_PRIORITY_URGENT_AUDIO = -19;
-  //   Process.THREAD_PRIORITY_URGENT_DISPLAY = -8;
-  // We use -6 for display, but we may want to split this
-  // into urgent (-8) and non-urgent (-4).
-  static const int threadPriorityAudio = -16;
-  static const int threadPriorityBackground = 10;
-  static const int threadPriorityDefault = 0;
-  static const int threadPriorityDisplay = -6;
-  switch (priority) {
-    case kThreadPriority_RealtimeAudio:
-      return threadPriorityAudio;
-    case kThreadPriority_Background:
-      return threadPriorityBackground;
-    case kThreadPriority_Normal:
-      return threadPriorityDefault;
-    case kThreadPriority_Display:
-      return threadPriorityDisplay;
-    default:
-      NOTREACHED() << "Unknown priority.";
-      return 0;
-  }
-}
-} // namespace
-
-//static
-void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
-                                       ThreadPriority priority) {
-  // On Android, we set the Audio priority through JNI as Audio priority
-  // will also allow the process to run while it is backgrounded.
-  if (priority == kThreadPriority_RealtimeAudio) {
-    JNIEnv* env = base::android::AttachCurrentThread();
-    Java_ThreadUtils_setThreadPriorityAudio(env, PlatformThread::CurrentId());
-    return;
-  }
-
-  // setpriority(2) will set a thread's priority if it is passed a tid as
-  // the 'process identifier', not affecting the rest of the threads in the
-  // process. Setting this priority will only succeed if the user has been
-  // granted permission to adjust nice values on the system.
-  DCHECK_NE(handle.id_, kInvalidThreadId);
-  int kNiceSetting = ThreadNiceValue(priority);
-  if (setpriority(PRIO_PROCESS, handle.id_, kNiceSetting))
-    LOG(ERROR) << "Failed to set nice value of thread to " << kNiceSetting;
-}
-
-void PlatformThread::SetName(const char* name) {
-  ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
-  tracked_objects::ThreadData::InitializeThreadContext(name);
-}
-
-
-void InitThreading() {
-}
-
-void InitOnThread() {
-  // Threads on linux/android may inherit their priority from the thread
-  // where they were created. This sets all new threads to the default.
-  PlatformThread::SetThreadPriority(PlatformThread::CurrentHandle(),
-                                    kThreadPriority_Normal);
-}
-
-void TerminateOnThread() {
-  base::android::DetachFromVM();
-}
-
-size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {
-  return 0;
-}
-
-bool RegisterThreadUtils(JNIEnv* env) {
-  return RegisterNativesImpl(env);
-}
-
-}  // namespace base
diff --git a/base/threading/platform_thread_linux.cc b/base/threading/platform_thread_linux.cc
deleted file mode 100644
index 42e12c7..0000000
--- a/base/threading/platform_thread_linux.cc
+++ /dev/null
@@ -1,103 +0,0 @@
-// 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.
-
-#include "base/threading/platform_thread.h"
-
-#include <errno.h>
-#include <sched.h>
-
-#include "base/lazy_instance.h"
-#include "base/logging.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/safe_strerror_posix.h"
-#include "base/threading/thread_id_name_manager.h"
-#include "base/threading/thread_restrictions.h"
-#include "base/tracked_objects.h"
-
-#if defined(OS_LINUX)
-#include <sys/prctl.h>
-#include <sys/resource.h>
-#include <sys/syscall.h>
-#include <sys/time.h>
-#include <unistd.h>
-#endif
-
-namespace base {
-
-namespace {
-int ThreadNiceValue(ThreadPriority priority) {
-  static const int threadPriorityAudio = -10;
-  static const int threadPriorityBackground = 10;
-  static const int threadPriorityDefault = 0;
-  static const int threadPriorityDisplay = -6;
-  switch (priority) {
-    case kThreadPriority_RealtimeAudio:
-      return threadPriorityAudio;
-    case kThreadPriority_Background:
-      return threadPriorityBackground;
-    case kThreadPriority_Normal:
-      return threadPriorityDefault;
-    case kThreadPriority_Display:
-      return threadPriorityDisplay;
-    default:
-      NOTREACHED() << "Unknown priority.";
-      return 0;
-  }
-}
-} // namespace
-
-// static
-void PlatformThread::SetName(const char* name) {
-  ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
-  tracked_objects::ThreadData::InitializeThreadContext(name);
-
-#ifndef OS_NACL
-  // On linux we can get the thread names to show up in the debugger by setting
-  // the process name for the LWP.  We don't want to do this for the main
-  // thread because that would rename the process, causing tools like killall
-  // to stop working.
-  if (PlatformThread::CurrentId() == getpid())
-    return;
-
-  // http://0pointer.de/blog/projects/name-your-threads.html
-  // Set the name for the LWP (which gets truncated to 15 characters).
-  // Note that glibc also has a 'pthread_setname_np' api, but it may not be
-  // available everywhere and it's only benefit over using prctl directly is
-  // that it can set the name of threads other than the current thread.
-  int err = prctl(PR_SET_NAME, name);
-  // We expect EPERM failures in sandboxed processes, just ignore those.
-  if (err < 0 && errno != EPERM)
-    DPLOG(ERROR) << "prctl(PR_SET_NAME)";
-#endif
-}
-
-// static
-void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
-                                       ThreadPriority priority) {
-#ifndef OS_NACL
-  // setpriority(2) will set a thread's priority if it is passed a tid as
-  // the 'process identifier', not affecting the rest of the threads in the
-  // process. Setting this priority will only succeed if the user has been
-  // granted permission to adjust nice values on the system.
-  DCHECK_NE(handle.id_, kInvalidThreadId);
-  int kNiceSetting = ThreadNiceValue(priority);
-  if (setpriority(PRIO_PROCESS, handle.id_, kNiceSetting))
-    LOG(ERROR) << "Failed to set nice value of thread to " << kNiceSetting;
-#endif
-}
-
-void InitThreading() {
-}
-
-void InitOnThread() {
-}
-
-void TerminateOnThread() {
-}
-
-size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {
-  return 0;
-}
-
-}  // namespace base
diff --git a/base/threading/platform_thread_mac.mm b/base/threading/platform_thread_mac.mm
index d81a286..48041a0 100644
--- a/base/threading/platform_thread_mac.mm
+++ b/base/threading/platform_thread_mac.mm
@@ -5,12 +5,10 @@
 #include "base/threading/platform_thread.h"
 
 #import <Foundation/Foundation.h>
-#include <algorithm>
 #include <dlfcn.h>
 #include <mach/mach.h>
 #include <mach/mach_time.h>
 #include <mach/thread_policy.h>
-#include <sys/resource.h>
 
 #include "base/lazy_instance.h"
 #include "base/logging.h"
@@ -165,7 +163,7 @@ void SetPriorityRealtimeAudio(mach_port_t mach_thread_id) {
 void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
                                        ThreadPriority priority) {
   // Convert from pthread_t to mach thread identifier.
-  mach_port_t mach_thread_id = pthread_mach_thread_np(handle.handle_);
+  mach_port_t mach_thread_id = pthread_mach_thread_np(handle);
 
   switch (priority) {
     case kThreadPriority_Normal:
@@ -174,51 +172,7 @@ void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
     case kThreadPriority_RealtimeAudio:
       SetPriorityRealtimeAudio(mach_thread_id);
       break;
-    default:
-      NOTREACHED() << "Unknown priority.";
-      break;
-  }
-}
-
-size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {
-#if defined(OS_IOS)
-  return 0;
-#else
-  // The Mac OS X default for a pthread stack size is 512kB.
-  // Libc-594.1.4/pthreads/pthread.c's pthread_attr_init uses
-  // DEFAULT_STACK_SIZE for this purpose.
-  //
-  // 512kB isn't quite generous enough for some deeply recursive threads that
-  // otherwise request the default stack size by specifying 0. Here, adopt
-  // glibc's behavior as on Linux, which is to use the current stack size
-  // limit (ulimit -s) as the default stack size. See
-  // glibc-2.11.1/nptl/nptl-init.c's __pthread_initialize_minimal_internal. To
-  // avoid setting the limit below the Mac OS X default or the minimum usable
-  // stack size, these values are also considered. If any of these values
-  // can't be determined, or if stack size is unlimited (ulimit -s unlimited),
-  // stack_size is left at 0 to get the system default.
-  //
-  // Mac OS X normally only applies ulimit -s to the main thread stack. On
-  // contemporary OS X and Linux systems alike, this value is generally 8MB
-  // or in that neighborhood.
-  size_t default_stack_size = 0;
-  struct rlimit stack_rlimit;
-  if (pthread_attr_getstacksize(&attributes, &default_stack_size) == 0 &&
-      getrlimit(RLIMIT_STACK, &stack_rlimit) == 0 &&
-      stack_rlimit.rlim_cur != RLIM_INFINITY) {
-    default_stack_size =
-        std::max(std::max(default_stack_size,
-                          static_cast<size_t>(PTHREAD_STACK_MIN)),
-                 static_cast<size_t>(stack_rlimit.rlim_cur));
   }
-  return default_stack_size;
-#endif
-}
-
-void InitOnThread() {
-}
-
-void TerminateOnThread() {
 }
 
 }  // namespace base
diff --git a/base/threading/platform_thread_posix.cc b/base/threading/platform_thread_posix.cc
index b1c0e9d..43e58b7 100644
--- a/base/threading/platform_thread_posix.cc
+++ b/base/threading/platform_thread_posix.cc
@@ -11,7 +11,6 @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/safe_strerror_posix.h"
-#include "base/synchronization/waitable_event.h"
 #include "base/threading/thread_id_name_manager.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/tracked_objects.h"
@@ -29,53 +28,74 @@
 #include <unistd.h>
 #endif
 
+#if defined(OS_ANDROID)
+#include <sys/resource.h>
+#include "base/android/thread_utils.h"
+#include "jni/ThreadUtils_jni.h"
+#endif
+
 namespace base {
 
+#if defined(OS_MACOSX)
 void InitThreading();
-void InitOnThread();
-void TerminateOnThread();
-size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes);
+#endif
 
 namespace {
 
 struct ThreadParams {
-  ThreadParams()
-      : delegate(NULL),
-        joinable(false),
-        priority(kThreadPriority_Normal),
-        handle(NULL),
-        handle_set(false, false) {
-  }
-
   PlatformThread::Delegate* delegate;
   bool joinable;
   ThreadPriority priority;
-  PlatformThreadHandle* handle;
-  WaitableEvent handle_set;
 };
 
+void SetCurrentThreadPriority(ThreadPriority priority) {
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+  switch (priority) {
+    case kThreadPriority_Normal:
+      NOTREACHED() << "Don't reset priority as not all processes can.";
+      break;
+    case kThreadPriority_RealtimeAudio:
+#if defined(OS_LINUX)
+      const int kNiceSetting = -10;
+      // Linux isn't posix compliant with setpriority(2), it will set a thread
+      // priority if it is passed a tid, not affecting the rest of the threads
+      // in the process.  Setting this priority will only succeed if the user
+      // has been granted permission to adjust nice values on the system.
+      if (setpriority(PRIO_PROCESS, PlatformThread::CurrentId(), kNiceSetting))
+        DVLOG(1) << "Failed to set nice value of thread to " << kNiceSetting;
+#elif defined(OS_ANDROID)
+      JNIEnv* env = base::android::AttachCurrentThread();
+      Java_ThreadUtils_setThreadPriorityAudio(env, PlatformThread::CurrentId());
+#endif  // defined(OS_LINUX)
+      break;
+  }
+#else  // !defined(OS_LINUX) && !defined(OS_ANDROID)
+  PlatformThread::SetThreadPriority(pthread_self(), priority);
+#endif
+}
+
 void* ThreadFunc(void* params) {
-  base::InitOnThread();
+#if defined(OS_ANDROID)
+  // Threads on linux/android may inherit their priority from the thread
+  // where they were created. This sets all threads to the default.
+  // TODO(epenner): Move thread priorities to base. (crbug.com/170549)
+  if (setpriority(PRIO_PROCESS, PlatformThread::CurrentId(), 0))
+    DVLOG(1) << "Failed to reset initial thread nice value to zero.";
+#endif
   ThreadParams* thread_params = static_cast<ThreadParams*>(params);
-
   PlatformThread::Delegate* delegate = thread_params->delegate;
   if (!thread_params->joinable)
     base::ThreadRestrictions::SetSingletonAllowed(false);
 
-  if (thread_params->priority != kThreadPriority_Normal) {
-    PlatformThread::SetThreadPriority(PlatformThread::CurrentHandle(),
-                                      thread_params->priority);
-  }
-
-  // Stash the id in the handle so the calling thread has a complete
-  // handle, and unblock the parent thread.
-  *(thread_params->handle) = PlatformThreadHandle(pthread_self(),
-                                                  PlatformThread::CurrentId());
-  thread_params->handle_set.Signal();
+  // If there is a non-default priority for this thread, set it now.
+  if (thread_params->priority != kThreadPriority_Normal)
+    SetCurrentThreadPriority(thread_params->priority);
 
+  delete thread_params;
   delegate->ThreadMain();
-
-  base::TerminateOnThread();
+#if defined(OS_ANDROID)
+  base::android::DetachFromVM();
+#endif
   return NULL;
 }
 
@@ -83,36 +103,60 @@ bool CreateThread(size_t stack_size, bool joinable,
                   PlatformThread::Delegate* delegate,
                   PlatformThreadHandle* thread_handle,
                   ThreadPriority priority) {
+#if defined(OS_MACOSX)
   base::InitThreading();
+#endif  // OS_MACOSX
 
   bool success = false;
   pthread_attr_t attributes;
   pthread_attr_init(&attributes);
 
-  // Pthreads are joinable by default, so only specify the detached
-  // attribute if the thread should be non-joinable.
+  // Pthreads are joinable by default, so only specify the detached attribute if
+  // the thread should be non-joinable.
   if (!joinable) {
     pthread_attr_setdetachstate(&attributes, PTHREAD_CREATE_DETACHED);
   }
 
-  // Get a better default if available.
-  if (stack_size == 0)
-    stack_size = base::GetDefaultThreadStackSize(attributes);
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  // The Mac OS X default for a pthread stack size is 512kB.
+  // Libc-594.1.4/pthreads/pthread.c's pthread_attr_init uses
+  // DEFAULT_STACK_SIZE for this purpose.
+  //
+  // 512kB isn't quite generous enough for some deeply recursive threads that
+  // otherwise request the default stack size by specifying 0. Here, adopt
+  // glibc's behavior as on Linux, which is to use the current stack size
+  // limit (ulimit -s) as the default stack size. See
+  // glibc-2.11.1/nptl/nptl-init.c's __pthread_initialize_minimal_internal. To
+  // avoid setting the limit below the Mac OS X default or the minimum usable
+  // stack size, these values are also considered. If any of these values
+  // can't be determined, or if stack size is unlimited (ulimit -s unlimited),
+  // stack_size is left at 0 to get the system default.
+  //
+  // Mac OS X normally only applies ulimit -s to the main thread stack. On
+  // contemporary OS X and Linux systems alike, this value is generally 8MB
+  // or in that neighborhood.
+  if (stack_size == 0) {
+    size_t default_stack_size;
+    struct rlimit stack_rlimit;
+    if (pthread_attr_getstacksize(&attributes, &default_stack_size) == 0 &&
+        getrlimit(RLIMIT_STACK, &stack_rlimit) == 0 &&
+        stack_rlimit.rlim_cur != RLIM_INFINITY) {
+      stack_size = std::max(std::max(default_stack_size,
+                                     static_cast<size_t>(PTHREAD_STACK_MIN)),
+                            static_cast<size_t>(stack_rlimit.rlim_cur));
+    }
+  }
+#endif  // OS_MACOSX && !OS_IOS
 
   if (stack_size > 0)
     pthread_attr_setstacksize(&attributes, stack_size);
 
-  ThreadParams params;
-  params.delegate = delegate;
-  params.joinable = joinable;
-  params.priority = priority;
-  params.handle = thread_handle;
-
-  pthread_t handle = 0;
-  int err = pthread_create(&handle,
-                           &attributes,
-                           ThreadFunc,
-                           &params);
+  ThreadParams* params = new ThreadParams;
+  params->delegate = delegate;
+  params->joinable = joinable;
+  params->priority = priority;
+
+  int err = pthread_create(thread_handle, &attributes, ThreadFunc, params);
   success = !err;
   if (!success) {
     errno = err;
@@ -120,13 +164,8 @@ bool CreateThread(size_t stack_size, bool joinable,
   }
 
   pthread_attr_destroy(&attributes);
-
-  // Don't let this call complete until the thread id
-  // is set in the handle.
-  if (success)
-    params.handle_set.Wait();
-  CHECK_EQ(handle, thread_handle->platform_handle());
-
+  if (!success)
+    delete params;
   return success;
 }
 
@@ -154,11 +193,6 @@ PlatformThreadId PlatformThread::CurrentId() {
 #endif
 }
 
-//static
-PlatformThreadHandle PlatformThread::CurrentHandle() {
-  return PlatformThreadHandle(pthread_self(), CurrentId());
-}
-
 // static
 void PlatformThread::YieldCurrentThread() {
   sched_yield();
@@ -179,6 +213,42 @@ void PlatformThread::Sleep(TimeDelta duration) {
     sleep_time = remaining;
 }
 
+#if defined(OS_LINUX)
+// static
+void PlatformThread::SetName(const char* name) {
+  ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
+  tracked_objects::ThreadData::InitializeThreadContext(name);
+
+  // On linux we can get the thread names to show up in the debugger by setting
+  // the process name for the LWP.  We don't want to do this for the main
+  // thread because that would rename the process, causing tools like killall
+  // to stop working.
+  if (PlatformThread::CurrentId() == getpid())
+    return;
+
+  // http://0pointer.de/blog/projects/name-your-threads.html
+  // Set the name for the LWP (which gets truncated to 15 characters).
+  // Note that glibc also has a 'pthread_setname_np' api, but it may not be
+  // available everywhere and it's only benefit over using prctl directly is
+  // that it can set the name of threads other than the current thread.
+  int err = prctl(PR_SET_NAME, name);
+  // We expect EPERM failures in sandboxed processes, just ignore those.
+  if (err < 0 && errno != EPERM)
+    DPLOG(ERROR) << "prctl(PR_SET_NAME)";
+}
+#elif defined(OS_MACOSX)
+// Mac is implemented in platform_thread_mac.mm.
+#else
+// static
+void PlatformThread::SetName(const char* name) {
+  ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
+  tracked_objects::ThreadData::InitializeThreadContext(name);
+
+  // (This should be relatively simple to implement for the BSDs; I
+  // just don't have one handy to test the code on.)
+}
+#endif  // defined(OS_LINUX)
+
 // static
 const char* PlatformThread::GetName() {
   return ThreadIdNameManager::GetInstance()->GetName(CurrentId());
@@ -187,7 +257,6 @@ const char* PlatformThread::GetName() {
 // static
 bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
                             PlatformThreadHandle* thread_handle) {
-  base::ThreadRestrictions::ScopedAllowWait allow_wait;
   return CreateThread(stack_size, true /* joinable thread */,
                       delegate, thread_handle, kThreadPriority_Normal);
 }
@@ -196,7 +265,6 @@ bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
 bool PlatformThread::CreateWithPriority(size_t stack_size, Delegate* delegate,
                                         PlatformThreadHandle* thread_handle,
                                         ThreadPriority priority) {
-  base::ThreadRestrictions::ScopedAllowWait allow_wait;
   return CreateThread(stack_size, true,  // joinable thread
                       delegate, thread_handle, priority);
 }
@@ -205,7 +273,6 @@ bool PlatformThread::CreateWithPriority(size_t stack_size, Delegate* delegate,
 bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) {
   PlatformThreadHandle unused;
 
-  base::ThreadRestrictions::ScopedAllowWait allow_wait;
   bool result = CreateThread(stack_size, false /* non-joinable thread */,
                              delegate, &unused, kThreadPriority_Normal);
   return result;
@@ -217,7 +284,21 @@ void PlatformThread::Join(PlatformThreadHandle thread_handle) {
   // the thread referred to by |thread_handle| may still be running long-lived /
   // blocking tasks.
   base::ThreadRestrictions::AssertIOAllowed();
-  pthread_join(thread_handle.handle_, NULL);
+  pthread_join(thread_handle, NULL);
+}
+
+#if !defined(OS_MACOSX) && !defined(OS_ANDROID)
+// Mac OS X uses lower-level mach APIs and Android uses Java APIs.
+// static
+void PlatformThread::SetThreadPriority(PlatformThreadHandle, ThreadPriority) {
+  // TODO(crogers): Implement, see http://crbug.com/116172
+}
+#endif
+
+#if defined(OS_ANDROID)
+bool RegisterThreadUtils(JNIEnv* env) {
+  return RegisterNativesImpl(env);
 }
+#endif  // defined(OS_ANDROID)
 
 }  // namespace base
diff --git a/base/threading/platform_thread_win.cc b/base/threading/platform_thread_win.cc
index 637fdfe..9e877b3 100644
--- a/base/threading/platform_thread_win.cc
+++ b/base/threading/platform_thread_win.cc
@@ -64,6 +64,7 @@ DWORD __stdcall ThreadFunc(void* params) {
 bool CreateThreadInternal(size_t stack_size,
                           PlatformThread::Delegate* delegate,
                           PlatformThreadHandle* out_thread_handle) {
+  PlatformThreadHandle thread_handle;
   unsigned int flags = 0;
   if (stack_size > 0 && base::win::GetVersion() >= base::win::VERSION_XP) {
     flags = STACK_SIZE_PARAM_IS_A_RESERVATION;
@@ -80,7 +81,7 @@ bool CreateThreadInternal(size_t stack_size,
   // have to work running on CreateThread() threads anyway, since we run code
   // on the Windows thread pool, etc.  For some background on the difference:
   //   http://www.microsoft.com/msj/1099/win32/win321099.aspx
-  void* thread_handle = CreateThread(
+  thread_handle = CreateThread(
       NULL, stack_size, ThreadFunc, params, flags, NULL);
   if (!thread_handle) {
     delete params;
@@ -88,7 +89,7 @@ bool CreateThreadInternal(size_t stack_size,
   }
 
   if (out_thread_handle)
-    *out_thread_handle = PlatformThreadHandle(thread_handle);
+    *out_thread_handle = thread_handle;
   else
     CloseHandle(thread_handle);
   return true;
@@ -102,12 +103,6 @@ PlatformThreadId PlatformThread::CurrentId() {
 }
 
 // static
-PlatformThreadHandle PlatformThread::CurrentHandle() {
-  NOTIMPLEMENTED(); // See OpenThread()
-  return kNullThreadHandle;
-}
-
-// static
 void PlatformThread::YieldCurrentThread() {
   ::Sleep(0);
 }
@@ -169,7 +164,7 @@ bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) {
 
 // static
 void PlatformThread::Join(PlatformThreadHandle thread_handle) {
-  DCHECK(thread_handle.handle_);
+  DCHECK(thread_handle);
   // TODO(willchan): Enable this check once I can get it to work for Windows
   // shutdown.
   // Joining another thread may block the current thread for a long time, since
@@ -181,17 +176,17 @@ void PlatformThread::Join(PlatformThreadHandle thread_handle) {
 
   // Wait for the thread to exit.  It should already have terminated but make
   // sure this assumption is valid.
-  DWORD result = WaitForSingleObject(thread_handle.handle_, INFINITE);
+  DWORD result = WaitForSingleObject(thread_handle, INFINITE);
   if (result != WAIT_OBJECT_0) {
     // Debug info for bug 127931.
     DWORD error = GetLastError();
     debug::Alias(&error);
     debug::Alias(&result);
-    debug::Alias(&thread_handle.handle_);
+    debug::Alias(&thread_handle);
     CHECK(false);
   }
 
-  CloseHandle(thread_handle.handle_);
+  CloseHandle(thread_handle);
 }
 
 // static
@@ -199,13 +194,10 @@ void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
                                        ThreadPriority priority) {
   switch (priority) {
     case kThreadPriority_Normal:
-      ::SetThreadPriority(handle.handle_, THREAD_PRIORITY_NORMAL);
+      ::SetThreadPriority(handle, THREAD_PRIORITY_NORMAL);
       break;
     case kThreadPriority_RealtimeAudio:
-      ::SetThreadPriority(handle.handle_, THREAD_PRIORITY_TIME_CRITICAL);
-      break;
-    default:
-      NOTREACHED() << "Unknown priority.";
+      ::SetThreadPriority(handle, THREAD_PRIORITY_TIME_CRITICAL);
       break;
   }
 }
diff --git a/base/threading/thread.cc b/base/threading/thread.cc
index 8b3dc2b..35e88a7 100644
--- a/base/threading/thread.cc
+++ b/base/threading/thread.cc
@@ -148,13 +148,6 @@ bool Thread::IsRunning() const {
   return running_;
 }
 
-void Thread::SetPriority(ThreadPriority priority) {
-  // The thread must be started (and id known) for this to be
-  // compatible with all platforms.
-  DCHECK_NE(thread_id_, kInvalidThreadId);
-  PlatformThread::SetThreadPriority(thread_, priority);
-}
-
 void Thread::Run(MessageLoop* message_loop) {
   message_loop->Run();
 }
diff --git a/base/threading/thread.h b/base/threading/thread.h
index 15f73a0..cf1a86d 100644
--- a/base/threading/thread.h
+++ b/base/threading/thread.h
@@ -142,9 +142,6 @@ class BASE_EXPORT Thread : PlatformThread::Delegate {
   // Returns true if the thread has been started, and not yet stopped.
   bool IsRunning() const;
 
-  // Sets the thread priority. The thread must already be started.
-  void SetPriority(ThreadPriority priority);
-
  protected:
   // Called just prior to starting the message loop
   virtual void Init() {}
diff --git a/base/threading/thread_restrictions.h b/base/threading/thread_restrictions.h
index 5abc8dc9..51cfa27 100644
--- a/base/threading/thread_restrictions.h
+++ b/base/threading/thread_restrictions.h
@@ -182,7 +182,6 @@ class BASE_EXPORT ThreadRestrictions {
   friend class SimpleThread;
   friend class Thread;
   friend class ThreadTestHelper;
-  friend class PlatformThread;
 
   // END ALLOWED USAGE.
   // BEGIN USAGE THAT NEEDS TO BE FIXED.