Bug 1377570 - Enable RCWN on mobile. r=valentin

This patch enables racing cache with network on mobile when cellular data isn't used.

mobile/android/app/mobile.js

@@ -106,10 +106,6 @@ pref("network.http.max-persistent-connections-per-proxy", 20);
 pref("network.http.spdy.push-allowance", 32768);
 pref("network.http.spdy.default-hpack-buffer", 4096); // 4k
 
-// Racing the cache with the network should be disabled to prevent accidental
-// data usage.
-pref("network.http.rcwn.enabled", false);
-
 // See bug 545869 for details on why these are set the way they are
 pref("network.buffer.cache.count", 24);
 pref("network.buffer.cache.size",  16384);

netwerk/protocol/http/nsHttpChannel.cpp

@@ -112,6 +112,7 @@
 #include "nsIMIMEInputStream.h"
 #include "nsIMultiplexInputStream.h"
 #include "../../cache2/CacheFileUtils.h"
+#include "nsINetworkLinkService.h"
 
 #ifdef MOZ_TASK_TRACER
 #include "GeckoTaskTracer.h"
@@ -9122,6 +9123,23 @@ nsHttpChannel::TriggerNetwork()
 nsresult
 nsHttpChannel::MaybeRaceCacheWithNetwork()
 {
+    nsresult rv;
+
+    nsCOMPtr<nsINetworkLinkService> netLinkSvc =
+        do_GetService(NS_NETWORK_LINK_SERVICE_CONTRACTID, &rv);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    uint32_t linkType;
+    rv = netLinkSvc->GetLinkType(&linkType);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    if (!(linkType == nsINetworkLinkService::LINK_TYPE_UNKNOWN ||
+          linkType == nsINetworkLinkService::LINK_TYPE_ETHERNET ||
+          linkType == nsINetworkLinkService::LINK_TYPE_USB ||
+          linkType == nsINetworkLinkService::LINK_TYPE_WIFI)) {
+        return NS_OK;
+    }
+
     // Don't trigger the network if the load flags say so.
     if (mLoadFlags & (LOAD_ONLY_FROM_CACHE | LOAD_NO_NETWORK_IO)) {
         return NS_OK;

toolkit/content/aboutNetworking.js

@@ -12,6 +12,8 @@ const gDashboard = Cc["@mozilla.org/network/dashboard;1"]
                      .getService(Ci.nsIDashboard);
 const gDirServ = Cc["@mozilla.org/file/directory_service;1"]
                    .getService(Ci.nsIDirectoryServiceProvider);
+const gNetLinkSvc = Cc["@mozilla.org/network/network-link-service;1"]
+                      .getService(Ci.nsINetworkLinkService);
 
 const gRequestNetworkingData = {
   "http": gDashboard.requestHttpConnections,
@@ -127,6 +129,14 @@ function displayWebsockets(data) {
 
 function displayRcwnStats(data) {
   let status = Services.prefs.getBoolPref("network.http.rcwn.enabled");
+  let linkType = gNetLinkSvc.linkType;
+  if (!(linkType == Ci.nsINetworkLinkService.LINK_TYPE_UNKNOWN ||
+        linkType == Ci.nsINetworkLinkService.LINK_TYPE_ETHERNET ||
+        linkType == Ci.nsINetworkLinkService.LINK_TYPE_USB ||
+        linkType == Ci.nsINetworkLinkService.LINK_TYPE_WIFI)) {
+    status = false;
+  }
+
   let cacheWon = data.rcwnCacheWonCount;
   let netWon = data.rcwnNetWonCount;
   let total = data.totalNetworkRequests;