Add a Mojo EDK for Chrome that uses one OS pipe per message pipe.

mojo/common/BUILD.gn

Index: mojo/common/BUILD.gn
diff --git a/mojo/common/BUILD.gn b/mojo/common/BUILD.gn
index 4be7ca6f4f99522cdb55e485d90d3a80d44a444c..832121ef7b73f025704b617308eea108a097d084 100644
--- a/mojo/common/BUILD.gn
+++ b/mojo/common/BUILD.gn
@@ -77,13 +77,23 @@ test("mojo_common_unittests") {
     "//mojo/environment:chromium",
     "//mojo/message_pump",
     "//testing/gtest",
-    "//third_party/mojo/src/mojo/edk/test:run_all_unittests",
-    "//third_party/mojo/src/mojo/edk/test:test_support",
     "//third_party/mojo/src/mojo/public/cpp/bindings",
     "//third_party/mojo/src/mojo/public/cpp/test_support:test_utils",
     "//url",
   ]
 
+  if (use_chrome_edk) {
+    deps += [
+      "//mojo/edk/test:run_all_unittests",
+      "//mojo/edk/test:test_support",
+    ]
+  } else {
+    deps += [
+      "//third_party/mojo/src/mojo/edk/test:run_all_unittests",
+      "//third_party/mojo/src/mojo/edk/test:test_support",
+    ]
+  }
+
   sources = [
     # The message_pump tests are so small and some what related to this code
     # that we put them here.