Move platform abstraction to base library

src/arm/simulator-arm.cc

Index: src/arm/simulator-arm.cc
diff --git a/src/arm/simulator-arm.cc b/src/arm/simulator-arm.cc
index e987825caee05ceb3e71603dbe06f681c449943c..3518bfa2c3b1310ab2ee743017cde5f1f5d92d88 100644
--- a/src/arm/simulator-arm.cc
+++ b/src/arm/simulator-arm.cc
@@ -451,7 +451,7 @@ void ArmDebugger::Debug() {
         }
       } else if (strcmp(cmd, "gdb") == 0) {
         PrintF("relinquishing control to gdb\n");
-        v8::internal::OS::DebugBreak();
+        v8::base::OS::DebugBreak();
         PrintF("regaining control from gdb\n");
       } else if (strcmp(cmd, "break") == 0) {
         if (argc == 2) {
@@ -3763,8 +3763,8 @@ int32_t Simulator::Call(byte* entry, int argument_count, ...) {
   int original_stack = get_register(sp);
   // Compute position of stack on entry to generated code.
   int entry_stack = (original_stack - (argument_count - 4) * sizeof(int32_t));
-  if (OS::ActivationFrameAlignment() != 0) {
-    entry_stack &= -OS::ActivationFrameAlignment();
+  if (base::OS::ActivationFrameAlignment() != 0) {
+    entry_stack &= -base::OS::ActivationFrameAlignment();
   }
   // Store remaining arguments on stack, from low to high memory.
   intptr_t* stack_argument = reinterpret_cast<intptr_t*>(entry_stack);