[Extensions] Set the channel to dev for extensions internals unittest

The extensions internals unittest relies on using the automation API
permission as an example of a manifest permission. Since this API is
restricted to the dev channel, it caused failures on trunk tests. To
solve this the feature channel is set manually for that particular test.

Bug: 986791
Change-Id: Ib107847f2c5eda6333a705e1f99a6e3e69e1f02b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1716245Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Tim Judkins <tjudkins@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680468}

chrome/browser/ui/webui/extensions/extensions_internals_unittest.cc

@@ -12,11 +12,13 @@
 #include "chrome/browser/extensions/permissions_updater.h"
 #include "chrome/browser/extensions/scripting_permissions_modifier.h"
 #include "chrome/test/base/testing_profile.h"
+#include "components/version_info/channel.h"
 #include "extensions/browser/event_router.h"
 #include "extensions/browser/event_router_factory.h"
 #include "extensions/browser/extension_prefs.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/common/extension_builder.h"
+#include "extensions/common/features/feature_channel.h"
 #include "extensions/common/permissions/api_permission.h"
 #include "extensions/common/permissions/api_permission_set.h"
 #include "extensions/common/permissions/manifest_permission_set.h"
@@ -42,6 +44,10 @@ std::unique_ptr<KeyedService> BuildEventRouter(
 // Test that active and optional permissions show up correctly in the JSON
 // returned by WriteToString.
 TEST_F(ExtensionsInternalsUnitTest, WriteToStringPermissions) {
+  // The automation manifest entry is restricted to the dev channel, so we do
+  // this so the test is fine on stable/beta.
+  extensions::ScopedCurrentChannel current_channel(version_info::Channel::DEV);
+
   InitializeEmptyExtensionService();
   extensions::EventRouterFactory::GetInstance()->SetTestingFactory(
       profile(), base::BindRepeating(&BuildEventRouter));