Inject file with sourceURL (#102)

This patch starts adding a sourceURL trailing comment to make stack traces
readable.

lib/Page.js

@@ -140,12 +140,13 @@ class Page extends EventEmitter {
    * @return {!Promise}
    */
   async injectFile(filePath) {
-    const contents = await new Promise((resolve, reject) => {
+    let contents = await new Promise((resolve, reject) => {
       fs.readFile(filePath, 'utf8', (err, data) => {
         if (err) return reject(err);
         resolve(data);
       });
     });
+    contents += `//# sourceURL=` + filePath.replace(/\n/g,'');
     return this._client.send('Runtime.evaluate', { expression: contents, returnByValue: true });
   }
 

test/assets/injectedfile.js

@@ -1 +1,2 @@
 __injected = 42;
+__injectedError = new Error('hi');

test/test.js

@@ -145,6 +145,12 @@ describe('Puppeteer', function() {
       const result = await page.evaluate(() => __injected);
       expect(result).toBe(42);
     }));
+    it('should include sourcemap', SX(async function() {
+      const helloPath = path.join(__dirname, './assets/injectedfile.js');
+      await page.injectFile(helloPath);
+      const result = await page.evaluate(() => __injectedError.stack);
+      expect(result).toContain('assets/injectedfile.js');
+    }));
   });
 
   describe('Frame.evaluate', function() {

third_party/phantomjs/test/basics/stacktrace.js

@@ -1,5 +1,3 @@
-//! unsupported
-
 // A SyntaxError leaks to phantom.onError, despite the try-catch.
 setup({ allow_uncaught_exception: true });
 
@@ -7,8 +5,8 @@ test(function () {
     var helperFile = "../fixtures/parse-error-helper.js";
     try {
         phantom.injectJs(helperFile);
+        assert_is_true(false);
     } catch (e) {
-        assert_equals(e.stack[0].file, helperFile);
-        assert_equals(e.stack[0].line, 2);
+        assert_is_true(e.stack.indexOf('fixtures/parse-error-helper.js:2') !== -1);
     }
 }, "stack trace from syntax error in injected file");