Add graceful handling of exceeding browser Performance API 150 entry limit

lib/Http/HttpModule.js

@@ -292,8 +292,15 @@ export default class HttpModule extends EventDispatcher {
         // XMLHttpRequest, we must wait for another process tick to check for a refreshed list.
         setTimeout((lastURLToken => {
             return () => {
+                let resourceEntries = performance.getEntriesByType('resource');
+
+                // Check the timing entries for possible browser limit.
+                if( resourceEntries.length >= 150 ) {
+                    console.warn('The browser Performance API may have exceeded its recommended limit of 150. See https://developer.mozilla.org/en-US/docs/Web/API/Performance/setResourceTimingBufferSize');
+                }
+
                 // Filter the timing entries to return only the one concerned by the last request made
-                let entries = performance.getEntriesByType('resource').filter(function(entry) {
+                let entries = resourceEntries.filter(function(entry) {
                     return ~entry.name.indexOf(lastURLToken);
                 });
 

lib/Http/LatencyModule.js

@@ -212,6 +212,11 @@ export default class LatencyModule extends HttpModule {
         // With Resource Timing API
         if (!xhr) {
             this._getTimingEntry(entry => {
+                if( !entry ) {
+                    console.warn(`Network JS could not find a performance entry for ${ this._lastURLToken }.`)
+                    return
+                }
+
                 // The latency calculation differs between an HTTP and an HTTPS connection
                 // See: http://www.w3.org/TR/resource-timing/#processing-model
                 let latency = !entry.secureConnectionStart