Add some METADATA files to control docs layout.

BUG=skia:3484
NOTRY=true
DOCS_PREVIEW= https://skia.org/?cl=976303002

Review URL: https://codereview.chromium.org/976303002

3 files changed, 28 insertions, 0 deletions

diff --git a/site/METADATA b/site/METADATA
new file mode 100644
index 0000000000..5c6310b188
--- /dev/null
+++ b/site/METADATA
@@ -0,0 +1,4 @@
+{
+  "dirOrder": ["user", "dev"],
+  "fileOrder": []
+}
diff --git a/site/dev/tools/markdown.md b/site/dev/tools/markdown.md
index ffdff4b576..e624a27239 100644
--- a/site/dev/tools/markdown.md
+++ b/site/dev/tools/markdown.md
@@ -34,6 +34,26 @@ the --port flag:
 
     docserver --preview --port=:8002
 
+METADATA
+--------
+
+By default all files and directories that appear in the same level are sorted
+alphabetically by file name in the navigation menu, with files appearing
+before directories. You can override this default behavior by adding a
+METADATA file to a directory. A METADATA file is a JSON file of the following
+format:
+
+~~~~
+   {
+     "dirOrder": ["sample", "quick", "special"],
+     "fileOrder": ["download", "api"]
+   }
+~~~~
+
+If a file or directory doesn't appear in `dirOrder` or `fileOrder` then it is sorted
+to appear after the members of `dirOrder` or `fileOrder` respectively. All
+files and directories that aren't controlled by a METADATA file are sorted in
+alphabetical order by their filename.
 
 Some Example MarkDown
 ---------------------
diff --git a/site/user/METADATA b/site/user/METADATA
new file mode 100644
index 0000000000..5d835d962b
--- /dev/null
+++ b/site/user/METADATA
@@ -0,0 +1,4 @@
+{
+  "dirOrder": ["sample", "quick", "special"],
+  "fileOrder": ["download", "api"]
+}