Update code to current Chromium master

This corresponds to:

Chromium: 6555f9456074c0c0e5f7713564b978588ac04a5d
webrtc: c8b569e0a7ad0b369e15f0197b3a558699ec8efa

webrtc/system_wrappers/include/static_instance.h

@@ -0,0 +1,153 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_SYSTEM_WRAPPERS_INCLUDE_STATIC_INSTANCE_H_
+#define WEBRTC_SYSTEM_WRAPPERS_INCLUDE_STATIC_INSTANCE_H_
+
+#include <assert.h>
+
+#include "webrtc/system_wrappers/include/critical_section_wrapper.h"
+#ifdef _WIN32
+#include "webrtc/system_wrappers/include/fix_interlocked_exchange_pointer_win.h"
+#endif
+
+namespace webrtc {
+
+enum CountOperation {
+  kRelease,
+  kAddRef,
+  kAddRefNoCreate
+};
+enum CreateOperation {
+  kInstanceExists,
+  kCreate,
+  kDestroy
+};
+
+template <class T>
+// Construct On First Use idiom. Avoids
+// "static initialization order fiasco".
+static T* GetStaticInstance(CountOperation count_operation) {
+  // TODO (hellner): use atomic wrapper instead.
+  static volatile long instance_count = 0;
+  static T* volatile instance = NULL;
+  CreateOperation state = kInstanceExists;
+#ifndef _WIN32
+  // This memory is staticly allocated once. The application does not try to
+  // free this memory. This approach is taken to avoid issues with
+  // destruction order for statically allocated memory. The memory will be
+  // reclaimed by the OS and memory leak tools will not recognize memory
+  // reachable from statics leaked so no noise is added by doing this.
+  static CriticalSectionWrapper* crit_sect(
+    CriticalSectionWrapper::CreateCriticalSection());
+  CriticalSectionScoped lock(crit_sect);
+
+  if (count_operation ==
+      kAddRefNoCreate && instance_count == 0) {
+    return NULL;
+  }
+  if (count_operation ==
+      kAddRef ||
+      count_operation == kAddRefNoCreate) {
+    instance_count++;
+    if (instance_count == 1) {
+      state = kCreate;
+    }
+  } else {
+    instance_count--;
+    if (instance_count == 0) {
+      state = kDestroy;
+    }
+  }
+  if (state == kCreate) {
+    instance = T::CreateInstance();
+  } else if (state == kDestroy) {
+    T* old_instance = instance;
+    instance = NULL;
+    // The state will not change past this point. Release the critical
+    // section while deleting the object in case it would be blocking on
+    // access back to this object. (This is the case for the tracing class
+    // since the thread owned by the tracing class also traces).
+    // TODO(hellner): this is a bit out of place but here goes, de-couple
+    // thread implementation with trace implementation.
+    crit_sect->Leave();
+    if (old_instance) {
+      delete old_instance;
+    }
+    // Re-acquire the lock since the scoped critical section will release
+    // it.
+    crit_sect->Enter();
+    return NULL;
+  }
+#else  // _WIN32
+  if (count_operation ==
+      kAddRefNoCreate && instance_count == 0) {
+    return NULL;
+  }
+  if (count_operation == kAddRefNoCreate) {
+    if (1 == InterlockedIncrement(&instance_count)) {
+      // The instance has been destroyed by some other thread. Rollback.
+      InterlockedDecrement(&instance_count);
+      assert(false);
+      return NULL;
+    }
+    // Sanity to catch corrupt state.
+    if (instance == NULL) {
+      assert(false);
+      InterlockedDecrement(&instance_count);
+      return NULL;
+    }
+  } else if (count_operation == kAddRef) {
+    if (instance_count == 0) {
+      state = kCreate;
+    } else {
+      if (1 == InterlockedIncrement(&instance_count)) {
+        // InterlockedDecrement because reference count should not be
+        // updated just yet (that's done when the instance is created).
+        InterlockedDecrement(&instance_count);
+        state = kCreate;
+      }
+    }
+  } else {
+    int new_value = InterlockedDecrement(&instance_count);
+    if (new_value == 0) {
+      state = kDestroy;
+    }
+  }
+
+  if (state == kCreate) {
+    // Create instance and let whichever thread finishes first assign its
+    // local copy to the global instance. All other threads reclaim their
+    // local copy.
+    T* new_instance = T::CreateInstance();
+    if (1 == InterlockedIncrement(&instance_count)) {
+      InterlockedExchangePointer(reinterpret_cast<void * volatile*>(&instance),
+                                 new_instance);
+    } else {
+      InterlockedDecrement(&instance_count);
+      if (new_instance) {
+        delete static_cast<T*>(new_instance);
+      }
+    }
+  } else if (state == kDestroy) {
+    T* old_value = static_cast<T*>(InterlockedExchangePointer(
+        reinterpret_cast<void * volatile*>(&instance), NULL));
+    if (old_value) {
+      delete static_cast<T*>(old_value);
+    }
+    return NULL;
+  }
+#endif  // #ifndef _WIN32
+  return instance;
+}
+
+}  // namspace webrtc
+
+#endif  // WEBRTC_SYSTEM_WRAPPERS_INCLUDE_STATIC_INSTANCE_H_