Bug 1140542 - Support capturing secondary chrome windows; r=automatedtester

A <window> object may not exist in popup windows that are spawned from
a <window>.  document.documentElement is equivalent to <window> in
the case of the primary window, but lets us support the ChromeWindow's
document when it isn't.

--HG--
extra : commitid : GVJfQ7yGGdV
extra : rebase_source : af351c5bd91eb865c657a2f45479c5b360c50fc6
extra : amend_source : f3ddef37a7f663fcf4f049f13eac3cf94df2ad29

testing/marionette/client/marionette/tests/unit/test_screenshot.py

@@ -45,24 +45,33 @@ class ScreenCaptureTestCase(MarionetteTestCase):
 class Chrome(ScreenCaptureTestCase):
     @property
     def primary_window_dimensions(self):
-        return tuple(self.marionette.execute_script("""
-            let win = document.getElementsByTagName("window")[0];
-            let rect = win.getBoundingClientRect();
-            return [rect.width, rect.height];"""))
+        current_window = self.marionette.current_window_handle
+        self.marionette.switch_to_window(self.original_window)
+        with self.marionette.using_context("chrome"):
+            rv = tuple(self.marionette.execute_script("""
+                let el = document.getElementsByTagName("window")[0];
+                let rect = el.getBoundingClientRect();
+                return [rect.width, rect.height];
+                """))
+        self.marionette.switch_to_window(current_window)
+        return rv
 
     def setUp(self):
         ScreenCaptureTestCase.setUp(self)
         self.marionette.set_context("chrome")
+        self.original_window = self.marionette.current_window_handle
+
+    def tearDown(self):
+        self.marionette.switch_to_window(self.original_window)
 
     # A full chrome window screenshot is not the outer dimensions of
     # the window, but instead the bounding box of the <window> inside
     # <browser>.
     def test_window(self):
-        string = self.marionette.screenshot()
-        self.assert_png(string)
+        ss = self.marionette.screenshot()
+        self.assert_png(ss)
         self.assertEqual(self.primary_window_dimensions,
-                         self.get_image_dimensions(string))
-
+                         self.get_image_dimensions(ss))
 
     def test_chrome_delegation(self):
         with self.marionette.using_context("content"):
@@ -70,6 +79,22 @@ class Chrome(ScreenCaptureTestCase):
         chrome = self.marionette.screenshot()
         self.assertNotEqual(content, chrome)
 
+    # This tests that GeckoDriver#takeScreenshot uses
+    # currentContext.document.documentElement instead of looking for a
+    # <window> element, which does not exist for secondary windows.
+    def test_secondary_windows(self):
+        ss = self.marionette.screenshot()
+        self.marionette.execute_script("""
+            window.open('chrome://marionette/content/doesnotexist.xul',
+            'foo',
+            'chrome');
+            """)
+        self.marionette.switch_to_window("foo")
+        ss = self.marionette.screenshot()
+        size = self.get_image_dimensions(ss)
+        self.assert_png(ss)
+        self.assertNotEqual(self.primary_window_dimensions, size)
+
 
 class Content(ScreenCaptureTestCase):
     @property

testing/marionette/driver.js

@@ -2596,7 +2596,7 @@ GeckoDriver.prototype.takeScreenshot = function(cmd, resp) {
       if (this.appName == "B2G") {
         doc = win.document.body;
       } else {
-        doc = win.document.getElementsByTagName("window")[0];
+        doc = win.document.documentElement;
       }
       let docRect = doc.getBoundingClientRect();
       let width = docRect.width;