[wasm] Add iterators for opcodes or offsets of one function

test/unittests/wasm/ast-decoder-unittest.cc

Index: test/unittests/wasm/ast-decoder-unittest.cc
diff --git a/test/unittests/wasm/ast-decoder-unittest.cc b/test/unittests/wasm/ast-decoder-unittest.cc
index 0861e00be1d77732941f418901c868387d8b7170..872eef99f84fd2fd560887f5bc35e4c43c5af590 100644
--- a/test/unittests/wasm/ast-decoder-unittest.cc
+++ b/test/unittests/wasm/ast-decoder-unittest.cc
@@ -2669,7 +2669,7 @@ TEST_F(BytecodeIteratorTest, SimpleForeach) {
   WasmOpcode expected[] = {kExprI8Const, kExprIf,      kExprI8Const,
                            kExprElse,    kExprI8Const, kExprEnd};
   size_t pos = 0;
-  for (WasmOpcode opcode : iter) {
+  for (WasmOpcode opcode : iter.opcodes()) {
     if (pos >= arraysize(expected)) {
       EXPECT_TRUE(false);
       break;
@@ -2685,20 +2685,40 @@ TEST_F(BytecodeIteratorTest, ForeachTwice) {
   int count = 0;
 
   count = 0;
-  for (WasmOpcode opcode : iter) {
+  for (WasmOpcode opcode : iter.opcodes()) {
     USE(opcode);
     count++;
   }
   EXPECT_EQ(6, count);
 
   count = 0;
-  for (WasmOpcode opcode : iter) {
+  for (WasmOpcode opcode : iter.opcodes()) {
     USE(opcode);
     count++;
   }
   EXPECT_EQ(6, count);
 }
 
+TEST_F(BytecodeIteratorTest, ForeachOffset) {
+  byte code[] = {WASM_IF_ELSE(WASM_ZERO, WASM_ZERO, WASM_ZERO)};
+  BytecodeIterator iter(code, code + sizeof(code));
+  int count = 0;
+
+  count = 0;
+  for (auto offset : iter.offsets()) {
+    USE(offset);
+    count++;
+  }
+  EXPECT_EQ(6, count);
+
+  count = 0;
+  for (auto offset : iter.offsets()) {
+    USE(offset);
+    count++;
+  }
+  EXPECT_EQ(6, count);
+}
+
 TEST_F(BytecodeIteratorTest, WithAstDecls) {
   byte code[] = {1, 1, kLocalI32, WASM_I8(9), WASM_I8(11)};
   AstLocalDecls decls(zone());