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

chrome/browser/BUILD.gn

Index: chrome/browser/BUILD.gn
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index a8234becb6704dcdf3c2edefe63f746adafdf09f..de7720c849e5f95412052608609693bef0fa0f8d 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -314,7 +314,6 @@ source_set("browser") {
       "//third_party/leveldatabase",
       "//third_party/libaddressinput",
       "//third_party/libyuv",
-      "//third_party/mojo/src/mojo/edk/system",
       "//third_party/mojo/src/mojo/public/cpp/bindings",
       "//third_party/mojo/src/mojo/public/js",
       "//third_party/re2",
@@ -328,6 +327,12 @@ source_set("browser") {
       "//v8",
     ]
 
+    if (use_chrome_edk) {
+      deps += [ "//mojo/edk/system" ]
+    } else {
+      deps += [ "//third_party/mojo/src/mojo/edk/system" ]
+    }
+
     if (toolkit_views) {
       deps += [ "//ui/views" ]
     }