Bug 1288582 - Hide Adobe Primetime plugin on Windows < Vista. r=spohl

We're not going to get a supported Adobe GMP on WinXP, so we shouldn't download
it or show it in our add-on manager.


MozReview-Commit-ID: I3cNsStmzsV

--HG--
extra : rebase_source : b67c7cbec013f83bcf7d24cac99755faf1b5e07e

toolkit/modules/GMPUtils.jsm

@@ -79,8 +79,9 @@ this.GMPUtils = {
         this.maybeReportTelemetry(aPlugin.id,
                                   "VIDEO_EME_ADOBE_UNSUPPORTED_REASON",
                                   GMPPluginUnsupportedReason.NOT_WINDOWS);
-        return false;
       }
+      // Windows Vista and later only supported by Adobe EME.
+      return AppConstants.isPlatformAndVersionAtLeast("win", "6");
     } else if (aPlugin.id == WIDEVINE_ID) {
       // The Widevine plugin is available for Windows versions Vista and later
       // and Mac OSX 10.7 and later.

toolkit/mozapps/extensions/test/browser/browser_gmpProvider.js

@@ -381,7 +381,7 @@ add_task(function* testEmeSupport() {
     let doc = gManagerWindow.document;
     let item = get_addon_element(gManagerWindow, addon.id);
     if (addon.id == GMPScope.EME_ADOBE_ID) {
-      if (Services.appinfo.OS == "WINNT") {
+      if (AppConstants.isPlatformAndVersionAtLeast("win", "6")) {
         Assert.ok(item, "Adobe EME supported, found add-on element.");
       } else {
         Assert.ok(!item,