A64: Synchronize with r17441.

src/a64/cpu-a64.h

Index: src/a64/cpu-a64.h
diff --git a/src/a64/cpu-a64.h b/src/a64/cpu-a64.h
index 08a7edcea99f81211c16b18da7ae7a293a7e6a8d..969312b3c41ba1575abf70271daaa0504ab37c95 100644
--- a/src/a64/cpu-a64.h
+++ b/src/a64/cpu-a64.h
@@ -68,6 +68,19 @@ class CpuFeatures : public AllStatic {
 
   static unsigned supported_;
 
+  static bool VerifyCrossCompiling() {
+    // There are no optional features for A64.
+    ASSERT(cross_compile_ == 0);
+    return true;
+  }
+
+  static bool VerifyCrossCompiling(CpuFeature f) {
+    // There are no optional features for A64.
+    USE(f);
+    ASSERT(cross_compile_ == 0);
+    return true;
+  }
+
  private:
   // Return the content of the cache type register.
   static uint32_t GetCacheType();
@@ -83,6 +96,8 @@ class CpuFeatures : public AllStatic {
   // This isn't used (and is always 0), but it is required by V8.
   static unsigned found_by_runtime_probing_only_;
 
+  static unsigned cross_compile_;
+
   friend class PlatformFeatureScope;
   DISALLOW_COPY_AND_ASSIGN(CpuFeatures);
 };