[wasm] Remove the use of the "external" bit on OldFunctions section.

src/wasm/encoder.h

Index: src/wasm/encoder.h
diff --git a/src/wasm/encoder.h b/src/wasm/encoder.h
index 2be7fee2993c9aa5dee712c0b3a1f384c89ffdfd..869a09c01121e13892a7da89884686afce2eb936 100644
--- a/src/wasm/encoder.h
+++ b/src/wasm/encoder.h
@@ -28,8 +28,7 @@ class WasmFunctionEncoder : public ZoneObject {
   void Serialize(byte* buffer, byte** header, byte** body) const;
 
  private:
-  WasmFunctionEncoder(Zone* zone, LocalType return_type, bool exported,
-                      bool external);
+  WasmFunctionEncoder(Zone* zone, LocalType return_type, bool exported);
   friend class WasmFunctionBuilder;
   uint16_t signature_index_;
   ZoneVector<LocalType> params_;
@@ -38,11 +37,10 @@ class WasmFunctionEncoder : public ZoneObject {
   uint16_t local_f32_count_;
   uint16_t local_f64_count_;
   bool exported_;
-  bool external_;
   ZoneVector<uint8_t> body_;
   ZoneVector<char> name_;
 
-  bool HasName() const { return (exported_ || external_) && name_.size() > 0; }
+  bool HasName() const { return exported_ && name_.size() > 0; }
 };
 
 class WasmFunctionBuilder : public ZoneObject {
@@ -64,8 +62,7 @@ class WasmFunctionBuilder : public ZoneObject {
   uint32_t EmitEditableVarIntImmediate();
   void EditVarIntImmediate(uint32_t offset, const uint32_t immediate);
   void Exported(uint8_t flag);
-  void External(uint8_t flag);
-  void SetName(const unsigned char* name, int name_length);
+  void SetName(const char* name, int name_length);
   WasmFunctionEncoder* Build(Zone* zone, WasmModuleBuilder* mb) const;
 
  private:
@@ -75,7 +72,6 @@ class WasmFunctionBuilder : public ZoneObject {
   struct Type;
   ZoneVector<Type> locals_;
   uint8_t exported_;
-  uint8_t external_;
   ZoneVector<uint8_t> body_;
   ZoneVector<uint32_t> local_indices_;
   ZoneVector<char> name_;
@@ -109,6 +105,12 @@ class WasmModuleIndex : public ZoneObject {
   const byte* end_;
 };
 
+struct WasmFunctionImport {
+  uint32_t sig_index;
+  const char* name;
+  int name_length;
+};
+
 class WasmModuleWriter : public ZoneObject {
  public:
   WasmModuleIndex* WriteTo(Zone* zone) const;
@@ -116,6 +118,7 @@ class WasmModuleWriter : public ZoneObject {
  private:
   friend class WasmModuleBuilder;
   explicit WasmModuleWriter(Zone* zone);
+  ZoneVector<WasmFunctionImport> imports_;
   ZoneVector<WasmFunctionEncoder*> functions_;
   ZoneVector<WasmDataSegmentEncoder*> data_segments_;
   ZoneVector<FunctionSig*> signatures_;
@@ -127,13 +130,14 @@ class WasmModuleWriter : public ZoneObject {
 class WasmModuleBuilder : public ZoneObject {
  public:
   explicit WasmModuleBuilder(Zone* zone);
-  uint16_t AddFunction();
+  uint32_t AddFunction();
   uint32_t AddGlobal(MachineType type, bool exported);
   WasmFunctionBuilder* FunctionAt(size_t index);
   void AddDataSegment(WasmDataSegmentEncoder* data);
-  uint16_t AddSignature(FunctionSig* sig);
+  uint32_t AddSignature(FunctionSig* sig);
   void AddIndirectFunction(uint16_t index);
   void MarkStartFunction(uint16_t index);
+  uint32_t AddImport(const char* name, int name_length, FunctionSig* sig);
   WasmModuleWriter* Build(Zone* zone);
 
   struct CompareFunctionSigs {
@@ -144,6 +148,7 @@ class WasmModuleBuilder : public ZoneObject {
  private:
   Zone* zone_;
   ZoneVector<FunctionSig*> signatures_;
+  ZoneVector<WasmFunctionImport> imports_;
   ZoneVector<WasmFunctionBuilder*> functions_;
   ZoneVector<WasmDataSegmentEncoder*> data_segments_;
   ZoneVector<uint16_t> indirect_functions_;