Add functions to interact with ASan and MSan, and some sample uses

The sample uses are from when I debugged bug 617124. The change in neteq_network_stats_unittest.cc is a fix for a minor unrelated bug found by the try bots when I tried to land this CL (a test was passing uninitialized packet data to NetEq).

BUG=chromium:617124

Review-Url: https://codereview.webrtc.org/2293893002
Cr-Commit-Position: refs/heads/master@{#14034}

webrtc/base/array_view.h

@@ -130,6 +130,11 @@ class ArrayView final {
   size_t size_;
 };
 
+template <typename T>
+inline ArrayView<T> MakeArrayView(T* data, size_t size) {
+  return ArrayView<T>(data, size);
+}
+
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_ARRAY_VIEW_H_