Initial commit for video support for pbs (prebid#1706)

* initial commit for video support for pbs

* Don't mutate bidRequest

modules/prebidServerBidAdapter.js

@@ -105,7 +105,16 @@ function PrebidServer() {
   /* Prebid executes this function when the page asks to send out bid requests */
   baseAdapter.callBids = function(bidRequest) {
     const isDebug = !!getConfig('debug');
-    convertTypes(bidRequest.ad_units);
+    const adUnits = utils.cloneJson(bidRequest.ad_units);
+    adUnits.forEach(adUnit => {
+      let videoMediaType = utils.deepAccess(adUnit, 'mediaTypes.video');
+      if (videoMediaType) {
+        // pbs expects a ad_unit.video attribute if the imp is video
+        adUnit.video = Object.assign({}, videoMediaType);
+        delete adUnit.mediaTypes.video;
+      }
+    })
+    convertTypes(adUnits);
     let requestJson = {
       account_id: config.accountId,
       tid: bidRequest.tid,
@@ -114,7 +123,7 @@ function PrebidServer() {
       secure: config.secure,
       url: utils.getTopWindowUrl(),
       prebid_version: '$prebid.version$',
-      ad_units: bidRequest.ad_units.filter(hasSizes),
+      ad_units: adUnits.filter(hasSizes),
       is_debug: isDebug
     };