Convert ios_web_shell_test to GN.

ios/third_party/earl_grey/xctest_shell.mm

Index: ios/third_party/earl_grey/xctest_shell.mm
diff --git a/ios/third_party/earl_grey/xctest_shell.mm b/ios/third_party/earl_grey/xctest_shell.mm
new file mode 100644
index 0000000000000000000000000000000000000000..dea72985ce3c0b3632fe856367e6df72e6249b4e
--- /dev/null
+++ b/ios/third_party/earl_grey/xctest_shell.mm
@@ -0,0 +1,23 @@
+// Copyright 2016 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.
+
+#import <UIKit/UIKit.h>
+#import <XCTest/XCTest.h>
+
+// For Chrome on iOS we want to run EarlGrey tests (that are XCTests) for all
+// our build configurations (Debug, Release, ...). In addition, the symbols
+// visibility is configured to private by default. To simplify testing with
+// those constraints, our tests are compiled in the TEST_HOST target instead
+// of the .xctest bundle that all link against this single test (just there to
+// ensure that the bundle is not empty).
+
+@interface XCTestShellTests : XCTestCase
+@end
+
+@implementation XCTestShellTests
+
+- (void)testThatShouldPass {

[justincohen, 2016/07/21 18:42:05]

Does this need to be an xctest at all?  the empty shell_test.mm we use currently
just compiles an unused EmptyFile NSobject.?

[sdefresne, 2016/07/22 13:32:08]

No, changed to a empty class like in shell_test.mm

+}
+
+@end