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

mojo/shell/BUILD.gn

Index: mojo/shell/BUILD.gn
diff --git a/mojo/shell/BUILD.gn b/mojo/shell/BUILD.gn
index 38fca1e7c4865d3fb60e49884d305a9d0e82c3c9..56edec84f572d91324ce0407d58097349c250825 100644
--- a/mojo/shell/BUILD.gn
+++ b/mojo/shell/BUILD.gn
@@ -49,10 +49,15 @@ source_set("shell") {
     "//crypto:crypto",
     "//mojo/application/public/cpp:sources",
     "//url",
-    "//third_party/mojo/src/mojo/edk/system",
     "//mojo/environment:chromium",
     "//mojo/util:filename_util",
   ]
+
+  if (use_chrome_edk) {
+    deps += [ "//mojo/edk/system" ]
+  } else {
+    deps += [ "//third_party/mojo/src/mojo/edk/system" ]
+  }
 }
 
 test("mojo_shell_unittests") {
@@ -69,10 +74,15 @@ test("mojo_shell_unittests") {
     ":test_bindings",
     "//base",
     "//mojo/application/public/cpp",
-    "//third_party/mojo/src/mojo/edk/test:run_all_unittests",
     "//testing/gtest",
     "//url",
   ]
+
+  if (use_chrome_edk) {
+    deps += [ "//mojo/edk/test:run_all_unittests" ]
+  } else {
+    deps += [ "//third_party/mojo/src/mojo/edk/test:run_all_unittests" ]
+  }
 }
 
 mojom("test_bindings") {