Move mojo edk into mojo/edk

This creates a mojo/edk directory which contains the "embedder developer
kit" aka the set of code needed to embed mojo code.

mojo/edk/embedder = code from mojo/embedder
mojo/edk/system = code from mojo/system
mojo/edk/test = code used to test the previous two, from mojo/common/test

mojo/edk/ can only depend on mojo/public/, base/ and itself.

[email protected]
[email protected] for file renames

Committed: https://chromium.googlesource.com/chromium/src/+/ee7ff197a98da4636f33bd713de784948b487bd4

Review URL: https://codereview.chromium.org/621153003

Cr-Commit-Position: refs/heads/master@{#297986}
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index ad1530d0..4fdba5e 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -172,10 +172,10 @@
       "//content/app/resources",
       "//media",
       "//media/cast:net",
+      "//mojo/edk/system",
       "//mojo/environment:chromium",
       "//mojo/public/cpp/bindings",
       "//mojo/public/js/bindings",
-      "//mojo/system",
       "//net:extras",
       "//net:net_with_v8",
       "//storage/browser",