[WIP] Initial CallFunctionCallback builtin.

src/mips/macro-assembler-mips.h

Index: src/mips/macro-assembler-mips.h
diff --git a/src/mips/macro-assembler-mips.h b/src/mips/macro-assembler-mips.h
index 3b2539e408868d9cc2053549b51136444e803c32..0276320316c38c94971701c9569b35412604c6e6 100644
--- a/src/mips/macro-assembler-mips.h
+++ b/src/mips/macro-assembler-mips.h
@@ -1547,6 +1547,9 @@ const Operand& rt = Operand(zero_reg), BranchDelaySlot bd = PROTECT
   // via --debug-code.
   void AssertUndefinedOrAllocationSite(Register object, Register scratch);
 
+  // Abort if argument is not a valid API call result, enabled via --debug-code.
+  void AssertApiCallResult(Register object);
+
   // Abort execution if reg is not the root value with the given index,
   // enabled via --debug-code.
   void AssertIsRoot(Register reg, Heap::RootListIndex index);