Replace AudioSilenceDetector with an AudioPowerMonitor.

base/float_util.h

Index: base/float_util.h
diff --git a/base/float_util.h b/base/float_util.h
index 458e85965b29657bf4044837c4cd1c88263d5d98..90273106cd65193dbef7edeba2825e1c040adabb 100644
--- a/base/float_util.h
+++ b/base/float_util.h
@@ -13,7 +13,8 @@
 
 namespace base {
 
-inline bool IsFinite(const double& number) {
+template <typename Float>
+inline bool IsFinite(const Float& number) {
 #if defined(OS_POSIX)
   return std::isfinite(number) != 0;
 #elif defined(OS_WIN)
@@ -21,6 +22,15 @@ inline bool IsFinite(const double& number) {
 #endif
 }
 
+template <typename Float>
+inline bool IsNaN(const Float& number) {
+#if defined(OS_POSIX)
+  return std::isnan(number) != 0;
+#elif defined(OS_WIN)
+  return _isnan(number) != 0;
+#endif
+}
+
 }  // namespace base
 
 #endif  // BASE_FLOAT_UTIL_H_