Fix printing of deoptimized function.

runtime/vm/deopt_instructions.cc

Index: runtime/vm/deopt_instructions.cc
===================================================================
--- runtime/vm/deopt_instructions.cc	(revision 16998)
+++ runtime/vm/deopt_instructions.cc	(working copy)
@@ -14,6 +14,7 @@
 
 DEFINE_FLAG(bool, compress_deopt_info, true,
             "Compress the size of the deoptimization info for optimized code.");
+DECLARE_FLAG(bool, trace_deoptimization);
 
 DeoptimizationContext::DeoptimizationContext(intptr_t* to_frame_start,
                                              intptr_t to_frame_size,
@@ -443,6 +444,11 @@
     // Increment the deoptimization counter. This effectively increments each
     // function occurring in the optimized frame.
     function.set_deoptimization_counter(function.deoptimization_counter() + 1);
+    if (FLAG_trace_deoptimization) {
+      OS::PrintErr("Deoptimizing inlined %s (count %d)\n",
+          function.ToFullyQualifiedCString(),
+          function.deoptimization_counter());
+    }
     // Clear invocation counter so that hopefully the function gets reoptimized
     // only after more feedback has been collected.
     function.set_usage_counter(0);