Precompilation: Generate instance calls as IC calls that can switch to Megamoprhic calls.

runtime/vm/code_patcher_arm64.cc

Index: runtime/vm/code_patcher_arm64.cc
diff --git a/runtime/vm/code_patcher_arm64.cc b/runtime/vm/code_patcher_arm64.cc
index 4e0bbee3319ec94c4adca0bb221ca63c0e1a9158..53f26edd22f1629ad25c6634ba57e6f6be1b1d0c 100644
--- a/runtime/vm/code_patcher_arm64.cc
+++ b/runtime/vm/code_patcher_arm64.cc
@@ -109,6 +109,19 @@ RawFunction* CodePatcher::GetUnoptimizedStaticCallAt(
 }
 
 
+void CodePatcher::PatchSwitchableCallAt(uword return_address,
+                                        const Code& code,
+                                        const ICData& ic_data,
+                                        const MegamorphicCache& cache,
+                                        const Code& lookup_stub) {
+  ASSERT(code.ContainsInstructionAt(return_address));
+  SwitchableCallPattern call(return_address, code);
+  ASSERT(call.cache() == ic_data.raw());
+  call.SetLookupStub(lookup_stub);
+  call.SetCache(cache);
+}
+
+
 void CodePatcher::PatchNativeCallAt(uword return_address,
                                     const Code& code,
                                     NativeFunction target,