Fix ~InProcessUtilityThread DCHECK.

~InProcessUtilityThread calls Stop(), which calls
PlatformThread::Join().

So it needs to use ScopedAllowBaseSyncPrimitivesOutsideBlockingScope
instead of ThreadRestrictions::SetIOAllowed(true).

Change-Id: Idf729959a1a1d77902a623806560b1cc86299e6f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1637613Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Matthew Denton <mpdenton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#665038}

base/threading/thread_restrictions.h

@@ -139,6 +139,7 @@ class CategorizedWorkerPool;
 class DesktopCaptureDevice;
 class DWriteFontLookupTableBuilder;
 class GpuProcessTransportFactory;
+class InProcessUtilityThread;
 class NestedMessagePumpAndroid;
 class RenderWidgetHostViewMac;
 class RTCVideoDecoder;
@@ -455,6 +456,7 @@ class BASE_EXPORT ScopedAllowBaseSyncPrimitivesOutsideBlockingScope {
   friend class base::ScopedAllowThreadRecallForStackSamplingProfiler;
   friend class base::StackSamplingProfiler;
   friend class content::DesktopCaptureDevice;
+  friend class content::InProcessUtilityThread;
   friend class content::RTCVideoDecoder;
   friend class content::RTCVideoDecoderAdapter;
   friend class content::RTCVideoEncoder;

content/utility/in_process_utility_thread.cc

@@ -8,6 +8,7 @@
 #include "base/lazy_instance.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
+#include "base/threading/thread_restrictions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/child/child_process.h"
 #include "content/utility/utility_thread_impl.h"
@@ -21,14 +22,11 @@ static base::LazyInstance<base::Lock>::DestructorAtExit
 
 InProcessUtilityThread::InProcessUtilityThread(
     const InProcessChildThreadParams& params)
-    : Thread("Chrome_InProcUtilityThread"), params_(params) {
-}
+    : Thread("Chrome_InProcUtilityThread"), params_(params) {}
 
 InProcessUtilityThread::~InProcessUtilityThread() {
-  // Wait till in-process utility thread finishes clean up.
-  bool previous_value = base::ThreadRestrictions::SetIOAllowed(true);
+  base::ScopedAllowBaseSyncPrimitivesOutsideBlockingScope allow_thread_join;
   Stop();
-  base::ThreadRestrictions::SetIOAllowed(previous_value);
 }
 
 void InProcessUtilityThread::Init() {