Packager: accept relative --transformer paths everywhere.

Summary:
`react-native start` already ensures that the `--transformer` path is understood to be relative to CWD, not to the module that ends up importing that file. `react-native bundle` and `react-native dependencies` didn't up until this point.

**Test plan:** Ensured that `react-native bundle ... --transformer ./relative/path` works with this patch applied.
Closes https://github.com/facebook/react-native/pull/7857

Differential Revision: D3393777

fbshipit-source-id: 303a226fae9c8087c3dd3b2e8d004462ca66665e

local-cli/bundle/buildBundle.js

@@ -9,6 +9,7 @@
 
 const log = require('../util/log').out('bundle');
 const outputBundle = require('./output/bundle');
+const path = require('path');
 const Promise = require('promise');
 const saveAssets = require('./saveAssets');
 const Server = require('../../packager/react-packager/src/Server');
@@ -31,7 +32,7 @@ function buildBundle(args, config, output = outputBundle, packagerInstance) {
       assetRoots: config.getAssetRoots(),
       blacklistRE: config.getBlacklistRE(args.platform),
       getTransformOptionsModulePath: config.getTransformOptionsModulePath,
-      transformModulePath: args.transformer,
+      transformModulePath: path.resolve(args.transformer),
       extraNodeModules: config.extraNodeModules,
       nonPersistent: true,
       resetCache: args['reset-cache'],

local-cli/bundle/bundleCommandLineArgs.js

@@ -20,7 +20,7 @@ module.exports = [
     type: 'string',
   }, {
     command: 'transformer',
-    description: 'Specify a custom transformer to be used (absolute path)',
+    description: 'Specify a custom transformer to be used',
     type: 'string',
     default: require.resolve('../../packager/transformer'),
   }, {

local-cli/dependencies/dependencies.js

@@ -41,7 +41,7 @@ function _dependencies(argv, config, resolve, reject, packagerInstance) {
       command: 'transformer',
       type: 'string',
       default: require.resolve('../../packager/transformer'),
-      description: 'Specify a custom transformer to be used (absolute path)'
+      description: 'Specify a custom transformer to be used'
     }, {
       command: 'verbose',
       description: 'Enables logging',
@@ -59,7 +59,7 @@ function _dependencies(argv, config, resolve, reject, packagerInstance) {
     assetRoots: config.getAssetRoots(),
     blacklistRE: config.getBlacklistRE(args.platform),
     getTransformOptionsModulePath: config.getTransformOptionsModulePath,
-    transformModulePath: args.transformer,
+    transformModulePath: path.resolve(args.transformer),
     extraNodeModules: config.extraNodeModules,
     verbose: config.verbose,
   };

local-cli/server/runServer.js

@@ -13,7 +13,6 @@ const connect = require('connect');
 const cpuProfilerMiddleware = require('./middleware/cpuProfilerMiddleware');
 const getDevToolsMiddleware = require('./middleware/getDevToolsMiddleware');
 const http = require('http');
-const isAbsolutePath = require('absolute-path');
 const loadRawBodyMiddleware = require('./middleware/loadRawBodyMiddleware');
 const messageSocket = require('./util/messageSocket.js');
 const openStackFrameInEditorMiddleware = require('./middleware/openStackFrameInEditorMiddleware');
@@ -68,18 +67,13 @@ function runServer(args, config, readyCallback) {
 }
 
 function getPackagerServer(args, config) {
-  let transformerPath = args.transformer;
-  if (!isAbsolutePath(transformerPath)) {
-    transformerPath = path.resolve(process.cwd(), transformerPath);
-  }
-
   return ReactPackager.createServer({
     nonPersistent: args.nonPersistent,
     projectRoots: args.projectRoots,
     blacklistRE: config.getBlacklistRE(),
     cacheVersion: '3',
     getTransformOptionsModulePath: config.getTransformOptionsModulePath,
-    transformModulePath: transformerPath,
+    transformModulePath: path.resolve(args.transformer),
     extraNodeModules: config.extraNodeModules,
     assetRoots: args.assetRoots,
     assetExts: [

local-cli/server/server.js

@@ -55,7 +55,7 @@ function _server(argv, config, resolve, reject) {
     command: 'transformer',
     type: 'string',
     default: require.resolve('../../packager/transformer'),
-    description: 'Specify a custom transformer to be used (absolute path)'
+    description: 'Specify a custom transformer to be used'
   }, {
     command: 'resetCache',
     description: 'Removes cached files',