Move platform abstraction to base library

test/cctest/test-code-stubs-x64.cc

Index: test/cctest/test-code-stubs-x64.cc
diff --git a/test/cctest/test-code-stubs-x64.cc b/test/cctest/test-code-stubs-x64.cc
index e9b35e3f0f65cf5fdb715d6c26d1b695e3812d0f..b58b073f3b7939736499e39caa4fea653634a53c 100644
--- a/test/cctest/test-code-stubs-x64.cc
+++ b/test/cctest/test-code-stubs-x64.cc
@@ -29,10 +29,10 @@
 
 #include "src/v8.h"
 
+#include "src/base/platform/platform.h"
 #include "src/code-stubs.h"
 #include "src/factory.h"
 #include "src/macro-assembler.h"
-#include "src/platform.h"
 #include "test/cctest/cctest.h"
 #include "test/cctest/test-code-stubs.h"
 
@@ -46,9 +46,8 @@ ConvertDToIFunc MakeConvertDToIFuncTrampoline(Isolate* isolate,
                                               Register destination_reg) {
   // Allocate an executable page of memory.
   size_t actual_size;
-  byte* buffer = static_cast<byte*>(OS::Allocate(Assembler::kMinimalBufferSize,
-                                                   &actual_size,
-                                                   true));
+  byte* buffer = static_cast<byte*>(v8::base::OS::Allocate(
+      Assembler::kMinimalBufferSize, &actual_size, true));
   CHECK(buffer);
   HandleScope handles(isolate);
   MacroAssembler assm(isolate, buffer, static_cast<int>(actual_size));