Add support for transparent background API

chrome/browser/extensions/api/app_window/app_window_apitest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "apps/app_window.h"
 #include "apps/app_window_registry.h"
 #include "apps/ui/native_app_window.h"
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "chrome/browser/apps/app_browsertest_util.h"
@@ skipping 90 matching lines @@
                        WindowsApiAlwaysOnTopNoPermissions) {
   EXPECT_TRUE(RunPlatformAppTest(
       "platform_apps/windows_api_always_on_top/no_permissions")) << message_;
 }
 
 IN_PROC_BROWSER_TEST_F(PlatformAppBrowserTest, WindowsApiGet) {
   EXPECT_TRUE(RunPlatformAppTest("platform_apps/windows_api_get"))
       << message_;
 }
 
+IN_PROC_BROWSER_TEST_F(PlatformAppBrowserTest,
+                       WindowsApiAlphaEnabledHasPermissions) {

[benwells, 2014/05/12 04:25:17]

Please also add a test for running this in stable channel. See
https://codereview.chromium.org/267303003/ for an example of how to do this (the
test is being altered in the CL).

[garykac, 2014/07/09 23:19:21]

Done, but on Stable requesting app.window.shape prevents the extension from
loading at all, which gives a warning in the test that can't be caught (AFAICT).

This warning can be ignored with the kFlagIgnoreManifestWarnings flag, but then
the extension is loaded and runs even though it shouldn't (because it is Stable
channel).

I fixed this by adding a check for Stable channel in app_window_api.cc, even
though it is redundant (since the permissions means that it should never be
hit). This might be overkill, but the code will be deleted once this feature
goes to Stable.

+#if defined(USE_AURA)

[benwells, 2014/05/12 04:25:17]

So ... if aura is enabled, alphaEnabled will be true if requested? Does this
mean it is true on windows outside of ash? Shouldn't it be false on windows
outside of ash?

[garykac, 2014/07/09 23:19:21]

Changed all the #ifdefs to use USE_ASH.

+  EXPECT_TRUE(RunPlatformAppTest(
+      "platform_apps/windows_api_alpha_enabled/has_permissions_aura"))
+      << message_;
+#else
+  EXPECT_TRUE(RunPlatformAppTest(
+      "platform_apps/windows_api_alpha_enabled/has_permissions_no_aura"))
+      << message_;
+#endif
+}
+
+IN_PROC_BROWSER_TEST_F(PlatformAppBrowserTest,
+                       WindowsApiAlphaEnabledNoPermissions) {
+  EXPECT_TRUE(RunPlatformAppTest(
+      "platform_apps/windows_api_alpha_enabled/no_permissions"))
+      << message_;
+}
+
 }  // namespace extensions