[wasm] Add support for import section.

test/mjsunit/wasm/wasm-constants.js

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --expose-wasm
 
 function bytes() {
   var buffer = new ArrayBuffer(arguments.length);
   var view = new Uint8Array(buffer);
   for (var i = 0; i < arguments.length; i++) {
     var val = arguments[i];
     if ((typeof val) == "string") val = val.charCodeAt(0);
     view[i] = val | 0;
   }
   return buffer;
 }
 
 // Section declaration constants
 var kDeclMemory = 0x00;
 var kDeclSignatures = 0x01;
 var kDeclFunctions = 0x02;
 var kDeclGlobals = 0x03;
 var kDeclDataSegments = 0x04;
 var kDeclFunctionTable = 0x05;
 var kDeclStartFunction = 0x07;
+var kDeclImportTable = 0x08;
 var kDeclEnd = 0x06;
 
 // Function declaration flags
 var kDeclFunctionName   = 0x01;
 var kDeclFunctionImport = 0x02;
 var kDeclFunctionLocals = 0x04;
 var kDeclFunctionExport = 0x08;
 
 // Local types
 var kAstStmt = 0;
@@ skipping 19 matching lines @@
 var kExprI32Const = 0x0a;
 var kExprI64Const = 0x0b;
 var kExprF64Const = 0x0c;
 var kExprF32Const = 0x0d;
 var kExprGetLocal = 0x0e;
 var kExprSetLocal = 0x0f;
 var kExprLoadGlobal = 0x10;
 var kExprStoreGlobal = 0x11;
 var kExprCallFunction = 0x12;
 var kExprCallIndirect = 0x13;
+var kExprCallImport = 0x1F;
 
 var kExprI32LoadMem8S = 0x20;
 var kExprI32LoadMem8U = 0x21;
 var kExprI32LoadMem16S = 0x22;
 var kExprI32LoadMem16U = 0x23;
 var kExprI64LoadMem8S = 0x24;
 var kExprI64LoadMem8U = 0x25;
 var kExprI64LoadMem16S = 0x26;
 var kExprI64LoadMem16U = 0x27;
 var kExprI64LoadMem32S = 0x28;
@@ skipping 165 matching lines @@
       }
       threwException = false;
     } catch (e) {
       assertEquals("string", typeof e);
       assertEquals(kTrapMsgs[trap], e);
       // Success.
       return;
     }
     throw new MjsUnitAssertionError("Did not trap, expected: " + kTrapMsgs[trap]);
 }