Move platform abstraction to base library

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index ecb8b19793625e6c67538a50822628bbdb3a96bf..c35fb9e506a5cd237f596962afd9d2b025a207fa 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -1144,7 +1144,7 @@ int MacroAssembler::ActivationFrameAlignment() {
   // environment.
   // Note: This will break if we ever start generating snapshots on one ARM
   // platform for another ARM platform with a different alignment.
-  return OS::ActivationFrameAlignment();
+  return base::OS::ActivationFrameAlignment();
 #else  // V8_HOST_ARCH_ARM
   // If we are using the simulator then we should always align to the expected
   // alignment. As the simulator is used to generate snapshots we do not know
@@ -3595,7 +3595,7 @@ void MacroAssembler::CallCFunctionHelper(Register function,
   // provides more information.
 #if V8_HOST_ARCH_ARM
   if (emit_debug_code()) {
-    int frame_alignment = OS::ActivationFrameAlignment();
+    int frame_alignment = base::OS::ActivationFrameAlignment();
     int frame_alignment_mask = frame_alignment - 1;
     if (frame_alignment > kPointerSize) {
       ASSERT(IsPowerOf2(frame_alignment));
@@ -4040,7 +4040,7 @@ CodePatcher::CodePatcher(byte* address,
 CodePatcher::~CodePatcher() {
   // Indicate that code has changed.
   if (flush_cache_ == FLUSH) {
-    CPU::FlushICache(address_, size_);
+    CpuFeatures::FlushICache(address_, size_);
   }
 
   // Check that the code was patched as expected.