Implement standalone event tracing in AppRTCDemo.

webrtc/base/atomicops.h

Index: webrtc/base/atomicops.h
diff --git a/webrtc/base/atomicops.h b/webrtc/base/atomicops.h
index b21bd999f304d2f9cd9742fceebd80b3722e7ce3..42b87097df845a68ba9ec0ca69df2dded0778f93 100644
--- a/webrtc/base/atomicops.h
+++ b/webrtc/base/atomicops.h
@@ -43,6 +43,16 @@ class AtomicOps {
                                         new_value,
                                         old_value);
   }
+  // Pointer variants.
+  template <typename T>
+  static T* AtomicLoadPtr(T* volatile* ptr) {
+    return *ptr;
+  }
+  template <typename T>
+  static T* CompareAndSwapPtr(T* volatile* ptr, T* old_value, T* new_value) {
+    return static_cast<T*>(::InterlockedCompareExchangePointer(
+        reinterpret_cast<PVOID volatile*>(ptr), old_value, new_value));
+  }
 #else
   static int Increment(volatile int* i) {
     return __sync_add_and_fetch(i, 1);
@@ -59,6 +69,15 @@ class AtomicOps {
   static int CompareAndSwap(volatile int* i, int old_value, int new_value) {
     return __sync_val_compare_and_swap(i, old_value, new_value);
   }
+  // Pointer variants.
+  template <typename T>
+  static T* AtomicLoadPtr(T* volatile* ptr) {
+    return __atomic_load_n(ptr, __ATOMIC_ACQUIRE);
+  }
+  template <typename T>
+  static T* CompareAndSwapPtr(T* volatile* ptr, T* old_value, T* new_value) {
+    return __sync_val_compare_and_swap(ptr, old_value, new_value);
+  }
 #endif
 };