Move platform abstraction to base library

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 16d0acd6e3caf045cb3bc470b71f7b3b841b18fa..3a2fe939a22da26b3618b51dad9f5f8195917d61 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -2183,9 +2183,9 @@ inline double FixedDoubleArray::hole_nan_as_double() {
 
 
 inline double FixedDoubleArray::canonical_not_the_hole_nan_as_double() {
-  ASSERT(BitCast<uint64_t>(OS::nan_value()) != kHoleNanInt64);
-  ASSERT((BitCast<uint64_t>(OS::nan_value()) >> 32) != kHoleNanUpper32);
-  return OS::nan_value();
+  ASSERT(BitCast<uint64_t>(base::OS::nan_value()) != kHoleNanInt64);
+  ASSERT((BitCast<uint64_t>(base::OS::nan_value()) >> 32) != kHoleNanUpper32);
+  return base::OS::nan_value();
 }
 
 
@@ -3952,11 +3952,11 @@ int32_t Int32ArrayTraits::defaultValue() { return 0; }
 
 
 float Float32ArrayTraits::defaultValue() {
-  return static_cast<float>(OS::nan_value());
+  return static_cast<float>(base::OS::nan_value());
 }
 
 
-double Float64ArrayTraits::defaultValue() { return OS::nan_value(); }
+double Float64ArrayTraits::defaultValue() { return base::OS::nan_value(); }
 
 
 template <class Traits>