docs: Add M Developer Preview devbyte to Preview landing page.

Change-Id: I61b2a6c4541de4155993ca8695e5bd3f6873b98a

docs/html/jd_collections.js

@@ -173,12 +173,12 @@ var RESOURCE_COLLECTIONS = {
   "preview/landing/more": {
     "title": "",
     "resources": [
+      "https://www.youtube.com/watch?v=yYU4DHLwoRk",
       "preview/features/runtime-permissions.html",
       "preview/behavior-changes.html",
       "preview/backup/index.html",
       "preview/features/app-linking.html",
-      "preview/testing/guide.html",
-      "preview/testing/performance.html",
+      "preview/testing/guide.html"
     ]
   },
   "distribute/landing/carousel": {

docs/html/jd_extras.js

@@ -2976,7 +2976,18 @@ DISTRIBUTE_RESOURCES = DISTRIBUTE_RESOURCES.concat([
     "lang":"en",
     "type":"distribute"
   },
-
+  {
+    "title":"Developing for Android 6.0 (Marshmallow)",
+    "titleFriendly":"",
+    "summary":"This video covers how to get started with the preview, important APIs to test and how to provide feedback on the preview.",
+    "url":"https://www.youtube.com/watch?v=yYU4DHLwoRk",
+    "group":"",
+    "keywords": ["Marshmallow", "Preview"],
+    "tags": [],
+    "image":"http://i1.ytimg.com/vi/yYU4DHLwoRk/maxresdefault.jpg",
+    "lang":"en",
+    "type":"Video"
+  },
 
   {
     "lang": "ja",