Also time external callbacks from generated code.

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 5b85a247d5bf32dbfb93e8294e815b919a25ead8..4e4f2c572c88097c74185c2ebc48a22cb6387e6f 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -720,11 +720,28 @@ void MacroAssembler::CallApiFunctionAndReturn(Address function_address,
   movq(prev_next_address_reg, Operand(base_reg, kNextOffset));
   movq(prev_limit_reg, Operand(base_reg, kLimitOffset));
   addl(Operand(base_reg, kLevelOffset), Immediate(1));
+
+  if (FLAG_log_timer_events) {
+    FrameScope frame(this, StackFrame::MANUAL);
+    PushSafepointRegisters();
+    PrepareCallCFunction(0);
+    CallCFunction(ExternalReference::log_enter_external_function(isolate()), 0);
+    PopSafepointRegisters();
+  }
+
   // Call the api function!
   movq(rax, reinterpret_cast<int64_t>(function_address),
        RelocInfo::RUNTIME_ENTRY);
   call(rax);
 
+  if (FLAG_log_timer_events) {
+    FrameScope frame(this, StackFrame::MANUAL);
+    PushSafepointRegisters();
+    PrepareCallCFunction(0);
+    CallCFunction(ExternalReference::log_leave_external_function(isolate()), 0);
+    PopSafepointRegisters();
+  }
+
 #if defined(_WIN64) && !defined(__MINGW64__)
   // rax keeps a pointer to v8::Handle, unpack it.
   movq(rax, Operand(rax, 0));