VM(RegExp): Allow OSR optimization of RegExp :matcher functions.

runtime/vm/kernel_binary_flowgraph.cc

Index: runtime/vm/kernel_binary_flowgraph.cc
diff --git a/runtime/vm/kernel_binary_flowgraph.cc b/runtime/vm/kernel_binary_flowgraph.cc
index 564ab5fb7acf1e247e17fdfdd8232a0e8f940b87..abd12463e294832acb9dd8565944c25f1f3971f0 100644
--- a/runtime/vm/kernel_binary_flowgraph.cc
+++ b/runtime/vm/kernel_binary_flowgraph.cc
@@ -3328,20 +3328,15 @@ FlowGraph* StreamingFlowGraphBuilder::BuildGraphOfFunction(
 
   normal_entry->LinkTo(body.entry);
 
+  GraphEntryInstr* graph_entry = flow_graph_builder_->graph_entry_;
   // When compiling for OSR, use a depth first search to prune instructions
   // unreachable from the OSR entry. Catch entries are always considered
   // reachable, even if they become unreachable after OSR.
   if (flow_graph_builder_->osr_id_ != Compiler::kNoOSRDeoptId) {
-    BitVector* block_marks =
-        new (Z) BitVector(Z, flow_graph_builder_->next_block_id_);
-    bool found = flow_graph_builder_->graph_entry_->PruneUnreachable(
-        flow_graph_builder_->graph_entry_, NULL, flow_graph_builder_->osr_id_,
-        block_marks);
-    ASSERT(found);
+    graph_entry->PruneUnreachableForOSR(Z, flow_graph_builder_->next_block_id_);
   }
-  return new (Z)
-      FlowGraph(*parsed_function(), flow_graph_builder_->graph_entry_,
-                flow_graph_builder_->next_block_id_ - 1);
+  return new (Z) FlowGraph(*parsed_function(), graph_entry,
+                           flow_graph_builder_->next_block_id_ - 1);
 }
 
 Fragment StreamingFlowGraphBuilder::BuildGetMainClosure() {