Add flag --inlining-callee-size-threshold (80), that prevents inlining too large functions.

runtime/vm/flow_graph_inliner.cc

Index: runtime/vm/flow_graph_inliner.cc
===================================================================
--- runtime/vm/flow_graph_inliner.cc	(revision 34652)
+++ runtime/vm/flow_graph_inliner.cc	(working copy)
@@ -34,6 +34,8 @@
     "Always inline functions that have threshold or fewer instructions");
 DEFINE_FLAG(int, inlining_callee_call_sites_threshold, 1,
     "Always inline functions containing threshold or fewer calls.");
+DEFINE_FLAG(int, inlining_callee_size_threshold, 80,
+    "Do not inline callees larger than threshold");
 DEFINE_FLAG(int, inlining_caller_size_threshold, 50000,
     "Stop inlining once caller reaches the threshold.");
 DEFINE_FLAG(int, inlining_constant_arguments_count, 1,
@@ -425,6 +427,9 @@
       // Prevent methods becoming humongous and thus slow to compile.
       return false;
     }
+    if (instr_count > FLAG_inlining_callee_size_threshold) {
+      return false;
+    }
     // 'instr_count' can be 0 if it was not computed yet.
     if ((instr_count != 0) && (instr_count <= FLAG_inlining_size_threshold)) {
       return true;