Add implementations of mojo::{Run,Terminate}[Main]Application() for "chromium".

mojo/application/BUILD.gn

Index: mojo/application/BUILD.gn
diff --git a/mojo/application/BUILD.gn b/mojo/application/BUILD.gn
index 08e7f955f709079205544e4ab05ae23afa89f563..f697dde380551db1e0e478f8af0f08b3faff6e63 100644
--- a/mojo/application/BUILD.gn
+++ b/mojo/application/BUILD.gn
@@ -6,6 +6,7 @@ source_set("application") {
   sources = [
     "application_runner_chromium.cc",
     "application_runner_chromium.h",
+    "run_application.cc",
   ]
 
   public_deps = [
@@ -13,9 +14,9 @@ source_set("application") {
   ]
   deps = [
     "//base",
+    "//mojo/environment:chromium",
     "//mojo/message_pump",
     "//mojo/public/cpp/system",
-    "//mojo/environment:chromium",
   ]
 }