ARM64: VIXL: Support a newer version of VIXL.

Please note that compiling VIXL with -Wshadow is a known VIXL issue.

This will be resolved in a later version of VIXL, when we can drop
the deprecated API for getters and setters.

For more info take a look at VIXL_DEPRECATED in the VIXL source code.

Change-Id: Iea30b1a7b065f9b16a92c6cc7ebdc50ef068b348
diff --git a/compiler/utils/arm64/assembler_arm64.cc b/compiler/utils/arm64/assembler_arm64.cc
index 22221e7..19450b3 100644
--- a/compiler/utils/arm64/assembler_arm64.cc
+++ b/compiler/utils/arm64/assembler_arm64.cc
@@ -36,7 +36,7 @@
 }
 
 size_t Arm64Assembler::CodeSize() const {
-  return vixl_masm_.GetBufferCapacity() - vixl_masm_.GetRemainingBufferSpace();
+  return vixl_masm_.GetSizeOfCodeGenerated();
 }
 
 const uint8_t* Arm64Assembler::CodeBufferBaseAddress() const {