First step to cleanup the power-of-2 mess.

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 13cba9d6bb4e564428ac488a2c60ee39edd2c6c8..85713ee23f26a8239be20f344d515c8965fe7b04 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -5,6 +5,7 @@
 #include "src/factory.h"
 
 #include "src/allocation-site-scopes.h"
+#include "src/base/bits.h"
 #include "src/conversions.h"
 #include "src/isolate-inl.h"
 #include "src/macro-assembler.h"
@@ -435,7 +436,8 @@ static inline Handle<String> MakeOrFindTwoCharacterString(Isolate* isolate,
   // when building the new string.
   if (static_cast<unsigned>(c1 | c2) <= String::kMaxOneByteCharCodeU) {
     // We can do this.
-    DCHECK(IsPowerOf2(String::kMaxOneByteCharCodeU + 1));  // because of this.
+    DCHECK(base::bits::IsPowerOfTwo32(String::kMaxOneByteCharCodeU +
+                                      1));  // because of this.
     Handle<SeqOneByteString> str =
         isolate->factory()->NewRawOneByteString(2).ToHandleChecked();
     uint8_t* dest = str->GetChars();