Vector ICs: Clear the vector ic slots appropriately during debugging.

src/debug.cc

Index: src/debug.cc
diff --git a/src/debug.cc b/src/debug.cc
index ef8bb2a6c1d61d952abeffb25e642c604717330c..ae9e284015ba3ea4f9ff93851afd11861bdfb2eb 100644
--- a/src/debug.cc
+++ b/src/debug.cc
@@ -321,6 +321,10 @@ void BreakLocation::ClearDebugBreak() {
   } else {
     // Restore the IC call.
     rinfo().set_target_address(original_rinfo().target_address());
+    // Some ICs store data in the feedback vector. Clear this to ensure we
+    // won't miss future stepping requirements.
+    SharedFunctionInfo* shared = debug_info_->shared();
+    shared->feedback_vector()->ClearICSlots(shared);
   }
   DCHECK(!IsDebugBreak());
 }
@@ -2118,6 +2122,10 @@ bool Debug::EnsureDebugInfo(Handle<SharedFunctionInfo> shared,
     return false;
   }
 
+  // Make sure IC state is clean.
+  shared->code()->ClearInlineCaches();
+  shared->feedback_vector()->ClearICSlots(*shared);
+
   // Create the debug info object.
   Handle<DebugInfo> debug_info = isolate->factory()->NewDebugInfo(shared);