Make access to SourceCode Native Extension lazy

Reviewed By: fromcelticpark

Differential Revision: D6987478

fbshipit-source-id: 6d600131239be34480bd1c5a0ca84b4fab360386

Author: Dmitry Zakharov

Libraries/Image/resolveAssetSource.js

@@ -17,11 +17,26 @@ const AssetSourceResolver = require('AssetSourceResolver');
 import type { ResolvedAssetSource } from 'AssetSourceResolver';
 
 let _customSourceTransformer, _serverURL, _scriptURL;
+
 let _sourceCodeScriptURL: ?string;
+function getSourceCodeScriptURL(): ?string {
+  if (_sourceCodeScriptURL) {
+    return _sourceCodeScriptURL;
+  }
+
+  let sourceCode = global.nativeExtensions && global.nativeExtensions.SourceCode;
+  if (!sourceCode) {
+    const NativeModules = require('NativeModules');
+    sourceCode = NativeModules && NativeModules.SourceCode;
+  }
+  _sourceCodeScriptURL = sourceCode.scriptURL;
+  return _sourceCodeScriptURL;
+}
 
 function getDevServerURL(): ?string {
   if (_serverURL === undefined) {
-    const match = _sourceCodeScriptURL && _sourceCodeScriptURL.match(/^https?:\/\/.*?\//);
+    const sourceCodeScriptURL = getSourceCodeScriptURL();
+    const match = sourceCodeScriptURL && sourceCodeScriptURL.match(/^https?:\/\/.*?\//);
     if (match) {
       // jsBundle was loaded from network
       _serverURL = match[0];
@@ -51,7 +66,7 @@ function _coerceLocalScriptURL(scriptURL: ?string): ?string {
 
 function getScriptURL(): ?string {
   if (_scriptURL === undefined) {
-    _scriptURL = _coerceLocalScriptURL(_sourceCodeScriptURL);
+    _scriptURL = _coerceLocalScriptURL(getSourceCodeScriptURL());
   }
   return _scriptURL;
 }
@@ -87,13 +102,6 @@ function resolveAssetSource(source: any): ?ResolvedAssetSource {
   return resolver.defaultAsset();
 }
 
-let sourceCode = global.nativeExtensions && global.nativeExtensions.SourceCode;
-if (!sourceCode) {
-  const NativeModules = require('NativeModules');
-  sourceCode = NativeModules && NativeModules.SourceCode;
-}
-_sourceCodeScriptURL = sourceCode && sourceCode.scriptURL;
-
 module.exports = resolveAssetSource;
 module.exports.pickScale = AssetSourceResolver.pickScale;
 module.exports.setCustomSourceTransformer = setCustomSourceTransformer;