Add gallery tests to rotate an image.

chrome/test/data/extensions/api_test/file_manager_browsertest/gallery/slide_mode.js

Index: chrome/test/data/extensions/api_test/file_manager_browsertest/gallery/slide_mode.js
diff --git a/chrome/test/data/extensions/api_test/file_manager_browsertest/gallery/slide_mode.js b/chrome/test/data/extensions/api_test/file_manager_browsertest/gallery/slide_mode.js
index 186ffe862a5447d22f70250609655e142ddd3c53..8a78b4dd588585699f9b06996a057b37d5cb9d70 100644
--- a/chrome/test/data/extensions/api_test/file_manager_browsertest/gallery/slide_mode.js
+++ b/chrome/test/data/extensions/api_test/file_manager_browsertest/gallery/slide_mode.js
@@ -5,47 +5,6 @@
 'use strict';
 
 /**
- * Waits until the expected image is shown.
- *
- * @param {document} document Document.
- * @param {number} width Expected width of the image.
- * @param {number} height Expected height of the image.
- * @param {string} name Expected name of the image.
- * @return {Promise} Promsie to be fulfilled when the check is passed.
- */
-function waitForSlideImage(document, width, height, name) {
-  var expected = {width: width, height: height, name: name};
-  return repeatUntil(function() {
-    var fullResCanvas = document.querySelector(
-        '.gallery[mode="slide"] .content canvas.fullres');
-    var nameBox = document.querySelector('.namebox');
-    var actual = {
-      width: fullResCanvas && fullResCanvas.width,
-      height: fullResCanvas && fullResCanvas.height,
-      name: nameBox && nameBox.value
-    };
-    if (!chrome.test.checkDeepEq(expected, actual)) {
-      return pending('Slide mode state, expected is %j, actual is %j.',
-                     expected, actual);
-    }
-    return actual;
-  });
-}
-
-/**
- * Shorthand for clicking an element.
- * @param {AppWindow} appWindow application window.
- * @param {string} query Query for the element.
- * @param {Promise} Promise to be fulfilled with the clicked element.
- */
-function waitAndClickElement(appWindow, query) {
-  return waitForElement(appWindow, query).then(function(element) {
-    element.click();
-    return element;
-  });
-}
-
-/**
  * Runs a test to traverse images in the slide mode.
  *
  * @param {string} testVolumeName Test volume name passed to the addEntries