Test for power of two safely

third_party/WebKit/Source/modules/webaudio/RealtimeAnalyser.cpp

Index: third_party/WebKit/Source/modules/webaudio/RealtimeAnalyser.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/RealtimeAnalyser.cpp b/third_party/WebKit/Source/modules/webaudio/RealtimeAnalyser.cpp
index b4cdd95f912dc21f77e63d440c30cef966929599..a0d1e56a3c068de3f3ff05750ab349935d068fe0 100644
--- a/third_party/WebKit/Source/modules/webaudio/RealtimeAnalyser.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/RealtimeAnalyser.cpp
@@ -63,11 +63,9 @@ RealtimeAnalyser::RealtimeAnalyser()
 bool RealtimeAnalyser::setFftSize(size_t size) {
   DCHECK(isMainThread());
 
-  // Only allow powers of two.
-  unsigned log2size = static_cast<unsigned>(log2(size));
-  bool isPOT(1UL << log2size == size);
-
-  if (!isPOT || size > MaxFFTSize || size < MinFFTSize)
+  // Only allow powers of two within the allowed range.
+  if (size > MaxFFTSize || size < MinFFTSize ||
+      !AudioUtilities::isPowerOfTwo(size))
     return false;
 
   if (m_fftSize != size) {