[ios] Compile ios/testing/earl_grey/matchers.mm under EG2.

This file is compiled as an EG2 test-side helper and removed from the
eg_app_support+eg2 target.

BUG=922813

Change-Id: Ia842d0c0feb9f662419a07e6d79761e71184e309
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1559383Reviewed-by: Justin Cohen <justincohen@chromium.org>
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#649314}

ios/testing/earl_grey/BUILD.gn

@@ -39,13 +39,15 @@ source_set("eg_app_support+eg2") {
     "coverage_utils.h",
     "coverage_utils.mm",
     "earl_grey_app.h",
-    "matchers.h",
-    "matchers.mm",
   ]
 }
 
 source_set("eg_test_support+eg2") {
-  configs += [ "//build/config/compiler:enable_arc" ]
+  defines = [ "CHROME_EARL_GREY_2" ]
+  configs += [
+    "//build/config/compiler:enable_arc",
+    "//build/config/ios:xctest_config",
+  ]
   testonly = true
 
   sources = [
@@ -53,6 +55,8 @@ source_set("eg_test_support+eg2") {
     "coverage_utils_stub.mm",
     "disabled_test_macros.h",
     "earl_grey_test.h",
+    "matchers.h",
+    "matchers.mm",
   ]
 
   deps = [

ios/testing/earl_grey/matchers.mm

@@ -3,7 +3,8 @@
 // found in the LICENSE file.
 
 #import "ios/testing/earl_grey/matchers.h"
-#include "ios/testing/earl_grey/earl_grey_app.h"
+
+#include "ios/testing/earl_grey/earl_grey_test.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."