Intrinsify _StringBase._substringMatches to speedup indexOf/startsWith/endsWith under precompilatio…

runtime/vm/intrinsifier_ia32.cc

Index: runtime/vm/intrinsifier_ia32.cc
diff --git a/runtime/vm/intrinsifier_ia32.cc b/runtime/vm/intrinsifier_ia32.cc
index a539284352df54c2b5f07c8422fcfcc2d5be3cc6..577775ea72bc5736241ab6395ac1605173f50bbd 100644
--- a/runtime/vm/intrinsifier_ia32.cc
+++ b/runtime/vm/intrinsifier_ia32.cc
@@ -1741,6 +1741,12 @@ void Intrinsifier::StringBaseCodeUnitAt(Assembler* assembler) {
 }
 
 
+// bool _substringMatches(int start, String other)
+void Intrinsifier::StringBaseSubstringMatches(Assembler* assembler) {
+  // For precompilation, not implemented on IA32.
+}
+
+
 void Intrinsifier::StringBaseCharAt(Assembler* assembler) {
   Label fall_through, try_two_byte_string;
   __ movl(EBX, Address(ESP, + 1 * kWordSize));  // Index.