Create an app snapshot of the Dart front end.

runtime/platform/globals.h

Index: runtime/platform/globals.h
diff --git a/runtime/platform/globals.h b/runtime/platform/globals.h
index d862a9edaf8ba2aeb33c489489b492f763179d35..6372df0e229326fc12df48279c470de5ce7ab284 100644
--- a/runtime/platform/globals.h
+++ b/runtime/platform/globals.h
@@ -462,6 +462,7 @@ const int kDoubleSize = sizeof(double);  // NOLINT
 const int kFloatSize = sizeof(float);    // NOLINT
 const int kQuadSize = 4 * kFloatSize;
 const int kSimd128Size = sizeof(simd128_value_t);  // NOLINT
+const int kInt64Size = sizeof(int64_t);            // NOLINT
 const int kInt32Size = sizeof(int32_t);            // NOLINT
 const int kInt16Size = sizeof(int16_t);            // NOLINT
 #ifdef ARCH_IS_32_BIT