Support parallel captures from the StackSamplingProfiler.

base/threading/thread_restrictions.h

 // 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.
 
 #ifndef BASE_THREADING_THREAD_RESTRICTIONS_H_
 #define BASE_THREADING_THREAD_RESTRICTIONS_H_
 
 #include "base/base_export.h"
 #include "base/logging.h"
 #include "base/macros.h"
 
 class BrowserProcessImpl;
 class HistogramSynchronizer;
 class NativeBackendKWallet;
 class ScopedAllowWaitForLegacyWebViewApi;
 
+namespace base {
+class StackSamplingProfiler;
+}
+
 namespace cc {
 class CompletionEvent;
 class SingleThreadTaskGraphRunner;
 }
 namespace chromeos {
 class BlockingMethodCaller;
 namespace system {
 class StatisticsProviderImpl;
 }
 }
@@ skipping 140 matching lines @@
   static void AssertIOAllowed() {}
   static bool SetSingletonAllowed(bool allowed) { return true; }
   static void AssertSingletonAllowed() {}
   static void DisallowWaiting() {}
   static void AssertWaitAllowed() {}
 #endif
 
  private:
   // DO NOT ADD ANY OTHER FRIEND STATEMENTS, talk to jam or brettw first.
   // BEGIN ALLOWED USAGE.
+  friend class base::StackSamplingProfiler;
   friend class content::BrowserShutdownProfileDumper;
   friend class content::BrowserSurfaceViewManager;
   friend class content::BrowserTestBase;
   friend class content::NestedMessagePumpAndroid;
   friend class content::ScopedAllowWaitForAndroidLayoutTests;
   friend class content::ScopedAllowWaitForDebugURL;
   friend class ::HistogramSynchronizer;
   friend class internal::TaskTracker;
   friend class ::ScopedAllowWaitForLegacyWebViewApi;
   friend class cc::CompletionEvent;
@@ skipping 59 matching lines @@
 
     DISALLOW_COPY_AND_ASSIGN(ScopedAllowWait);
   };
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(ThreadRestrictions);
 };
 
 }  // namespace base
 
 #endif  // BASE_THREADING_THREAD_RESTRICTIONS_H_