Use std::pow in rtc_base/numerics.

Bug: webrtc:10433
Change-Id: If9d19a970e7bb2acc7782c9f9604dafccbb1d8ce
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/128606
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27208}
diff --git a/rtc_base/numerics/exp_filter.cc b/rtc_base/numerics/exp_filter.cc
index 0c6fb00..a58250a 100644
--- a/rtc_base/numerics/exp_filter.cc
+++ b/rtc_base/numerics/exp_filter.cc
@@ -10,7 +10,7 @@
 
 #include "rtc_base/numerics/exp_filter.h"
 
-#include <math.h>
+#include <cmath>
 
 namespace rtc {
 
@@ -28,7 +28,7 @@
   } else if (exp == 1.0) {
     filtered_ = alpha_ * filtered_ + (1 - alpha_) * sample;
   } else {
-    float alpha = pow(alpha_, exp);
+    float alpha = std::pow(alpha_, exp);
     filtered_ = alpha * filtered_ + (1 - alpha) * sample;
   }
   if (max_ != kValueUndefined && filtered_ > max_) {
diff --git a/rtc_base/numerics/exp_filter_unittest.cc b/rtc_base/numerics/exp_filter_unittest.cc
index 412dc77..46f01c8 100644
--- a/rtc_base/numerics/exp_filter_unittest.cc
+++ b/rtc_base/numerics/exp_filter_unittest.cc
@@ -8,7 +8,7 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include <math.h>
+#include <cmath>
 
 #include "rtc_base/numerics/exp_filter.h"
 #include "test/gtest.h"
@@ -26,7 +26,7 @@
 }
 
 TEST(ExpFilterTest, SecondTime) {
-  double value;
+  float value;
 
   ExpFilter filter = ExpFilter(0.9f);
   filter.Apply(100.0f, 10.0f);
@@ -35,7 +35,7 @@
   value = 10.0f;
 
   filter.Apply(10.0f, 20.0f);
-  double alpha = pow(0.9f, 10.0f);
+  float alpha = std::pow(0.9f, 10.0f);
   value = alpha * value + (1.0f - alpha) * 20.0f;
   EXPECT_FLOAT_EQ(value, filter.filtered());
 }