From 28a638ff22f598f6aa9388db6a4cf13fe9f11644 Mon Sep 17 00:00:00 2001
From: Hirokazu Honda <hiroh@google.com>
Date: Wed, 1 Aug 2018 17:03:18 +0900
Subject: [PATCH] ThreadLocalStorage: Add a function to destroy pthread key
 used in libchrome

MojoProcessSupport needs to destroy pthread key which is globally used in libchrome. The key is
stored in a local variable in thread_local_storage.cc.
This adds a function to destroy the key so that MojoProcessSupport can do it.

Bug: 110722333
Test: No crash in opening DRMInfo.app
Test: PlayStore still works
Test: cheets_ContainerSmokeTest and cheets_LoginScreen
Change-Id: Ib10c83deb5f7ef141d4ab9883e0d2c31d422a1b1
---
 base/threading/thread_local_storage.cc | 11 +++++++++++
 base/threading/thread_local_storage.h  |  7 +++++++
 2 files changed, 18 insertions(+)

diff --git a/base/threading/thread_local_storage.cc b/base/threading/thread_local_storage.cc
index 48c1dd5..90ae69e 100644
--- a/base/threading/thread_local_storage.cc
+++ b/base/threading/thread_local_storage.cc
@@ -247,6 +247,17 @@ void PlatformThreadLocalStorage::OnThreadExit() {
 void PlatformThreadLocalStorage::OnThreadExit(void* value) {
   OnThreadExitInternal(static_cast<TlsVectorEntry*>(value));
 }
+
+// static
+void PlatformThreadLocalStorage::ForceFreeTLS() {
+  PlatformThreadLocalStorage::TLSKey key =
+      base::subtle::NoBarrier_AtomicExchange(
+          &g_native_tls_key,
+          PlatformThreadLocalStorage::TLS_KEY_OUT_OF_INDEXES);
+  if (key == PlatformThreadLocalStorage::TLS_KEY_OUT_OF_INDEXES)
+    return;
+  PlatformThreadLocalStorage::FreeTLS(key);
+}
 #endif  // defined(OS_WIN)
 
 }  // namespace internal
diff --git a/base/threading/thread_local_storage.h b/base/threading/thread_local_storage.h
index fd2a789..c5c7759 100644
--- a/base/threading/thread_local_storage.h
+++ b/base/threading/thread_local_storage.h
@@ -75,6 +75,13 @@ class BASE_EXPORT PlatformThreadLocalStorage {
   // GetTLSValue() to retrieve the value of slot as it has already been reset
   // in Posix.
   static void OnThreadExit(void* value);
+  // Normally, Chrome runs as a process, so freeing the TLS is not needed since
+  // the OS will perform that while it's reclaiming the process' memory upon
+  // termination. If, however, this code is used inside a library that is
+  // dynamically loaded and unloaded, the consumer is responsible for calling
+  // this after all Chrome threads have stopped and prior to unloading the
+  // library.
+  static void ForceFreeTLS();
 #endif
 };
 
-- 
2.18.0.345.g5c9ce644c3-goog