Fix MacroAssembler::Prologue for Arm when FLAG_out_off_line_constant_pool is enabled.

The prologue update in r21329 changed the scoping of the PredictableCodeSizeScope.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/284303003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21345 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/macro-assembler-arm.cc

@@ -915,21 +915,22 @@ void MacroAssembler::StubPrologue() {
 
 
 void MacroAssembler::Prologue(bool code_pre_aging) {
-  PredictableCodeSizeScope predictible_code_size_scope(
-      this, kNoCodeAgeSequenceLength);
-  // The following three instructions must remain together and unmodified
-  // for code aging to work properly.
-  if (code_pre_aging) {
-    // Pre-age the code.
-    Code* stub = Code::GetPreAgedCodeAgeStub(isolate());
-    add(r0, pc, Operand(-8));
-    ldr(pc, MemOperand(pc, -4));
-    emit_code_stub_address(stub);
-  } else {
-    PushFixedFrame(r1);
-    nop(ip.code());
-    // Adjust FP to point to saved FP.
-    add(fp, sp, Operand(StandardFrameConstants::kFixedFrameSizeFromFp));
+  { PredictableCodeSizeScope predictible_code_size_scope(
+        this, kNoCodeAgeSequenceLength);
+    // The following three instructions must remain together and unmodified
+    // for code aging to work properly.
+    if (code_pre_aging) {
+      // Pre-age the code.
+      Code* stub = Code::GetPreAgedCodeAgeStub(isolate());
+      add(r0, pc, Operand(-8));
+      ldr(pc, MemOperand(pc, -4));
+      emit_code_stub_address(stub);
+    } else {
+      PushFixedFrame(r1);
+      nop(ip.code());
+      // Adjust FP to point to saved FP.
+      add(fp, sp, Operand(StandardFrameConstants::kFixedFrameSizeFromFp));
+    }
   }
   if (FLAG_enable_ool_constant_pool) {
     LoadConstantPoolPointerRegister();