Remove unnecessary front-end features and pres when not building EME.

Tag #26.

browser/app/profile/firefox.js

@@ -1330,20 +1330,21 @@ pref("identity.fxaccounts.migrateToDevEdition", false);
 pref("ui.key.menuAccessKeyFocuses", true);
 #endif
 
+#ifdef MOZ_EME
 // Encrypted media extensions.
-#ifdef XP_LINUX
-// On Linux EME is visible but disabled by default. This is so that the
-// "Play DRM content" checkbox in the Firefox UI is unchecked by default.
+// EME is visible but disabled by default. This is so that the
+// "Play DRM content" checkbox in the browser UI is unchecked by default.
 // DRM requires downloading and installing proprietary binaries, which
-// users on an open source operating systems didn't opt into. The first
-// time a site using EME is encountered, the user will be prompted to
-// enable DRM, whereupon the EME plugin binaries will be downloaded if
-// permission is granted.
+// users didn't necessarily opt-in to by installing the browser.
+// The first time a site using EME is encountered, the user will be
+// prompted to enable DRM, whereupon the EME plugin binaries will be
+// downloaded if permission is granted.
 pref("media.eme.enabled", false);
-#else
-pref("media.eme.enabled", true);
-#endif
 pref("media.eme.apiVisible", true);
+#else
+// Disable redundant interfaces
+pref("media.eme.apiVisible", false);
+#endif
 
 // Decode using Gecko Media Plugins in <video>, if a system decoder is not
 // availble and the preferred GMP is available.

browser/base/content/browser-media.js

@@ -5,12 +5,16 @@
 
 var gEMEHandler = {
   get uiEnabled() {
+#ifdef MOZ_EME
     let emeUIEnabled = Services.prefs.getBoolPref("browser.eme.ui.enabled");
     // Force-disable on WinXP:
     if (navigator.platform.toLowerCase().startsWith("win")) {
       emeUIEnabled = emeUIEnabled && parseFloat(Services.sysinfo.get("version")) >= 6;
     }
     return emeUIEnabled;
+#else
+    return false;
+#endif
   },
   ensureEMEEnabled: function(browser, keySystem) {
     Services.prefs.setBoolPref("media.eme.enabled", true);

browser/base/jar.mn

@@ -83,7 +83,7 @@ browser.jar:
         content/browser/browser-fullZoom.js           (content/browser-fullZoom.js)
         content/browser/browser-fxaccounts.js         (content/browser-fxaccounts.js)
         content/browser/browser-gestureSupport.js     (content/browser-gestureSupport.js)
-        content/browser/browser-media.js              (content/browser-media.js)
+*       content/browser/browser-media.js              (content/browser-media.js)
         content/browser/browser-places.js             (content/browser-places.js)
         content/browser/browser-plugins.js            (content/browser-plugins.js)
         content/browser/browser-refreshblocker.js     (content/browser-refreshblocker.js)

browser/components/preferences/in-content/content.js

@@ -78,6 +78,7 @@ var gContentPane = {
     document.getElementById("notificationsPolicyLearnMore").setAttribute("href",
                                                                          notificationInfoURL);
 
+#ifdef MOZ_EME
     let drmInfoURL =
       Services.urlFormatter.formatURLPref("app.support.baseURL") + "drm-content";
     document.getElementById("playDRMContentLink").setAttribute("href", drmInfoURL);
@@ -91,6 +92,7 @@ var gContentPane = {
       // of the pane hiding/showing code potentially interfering:
       document.getElementById("drmGroup").setAttribute("style", "display: none !important");
     }
+#endif
   },
 
   // UTILITY FUNCTIONS

browser/components/preferences/in-content/content.xul

@@ -6,10 +6,12 @@
 
 <preferences id="contentPreferences" hidden="true" data-category="paneContent">
 
+#ifdef MOZ_EME
   <!-- DRM content -->
   <preference id="media.eme.enabled"
               name="media.eme.enabled"
               type="bool"/>
+#endif
 
   <!-- Popups -->
   <preference id="dom.disable_open_during_load"
@@ -40,6 +42,7 @@
   <html:a class="help-button" target="_blank" aria-label="&helpButton.label;"></html:a>
 </hbox>
 
+#ifdef MOZ_EME
 <groupbox id="drmGroup" data-category="paneContent" hidden="true">
   <caption><label>&drmContent.label;</label></caption>
   <grid id="contentGrid2">
@@ -60,6 +63,7 @@
     </rows>
   </grid>
 </groupbox>
+#endif
 
 <groupbox id="notificationsGroup" data-category="paneContent" hidden="true">
   <caption><label>&notificationsPolicy.label;</label></caption>

browser/components/preferences/in-content/jar.mn

@@ -12,7 +12,7 @@ browser.jar:
    content/browser/preferences/in-content/containers.js
    content/browser/preferences/in-content/advanced.js
    content/browser/preferences/in-content/applications.js
-   content/browser/preferences/in-content/content.js
+*  content/browser/preferences/in-content/content.js
    content/browser/preferences/in-content/sync.js
    content/browser/preferences/in-content/security.js
    content/browser/preferences/in-content/search.js

mobile/android/app/mobile.js

@@ -627,6 +627,12 @@ pref("media.mediasource.enabled", true);
 
 pref("media.mediadrm-widevinecdm.visible", true);
 
+#ifdef MOZ_EME
+// Enable EME(Encrypted media extensions?)
+pref("media.eme.enabled", false);
+pref("media.eme.apiVisible", false);
+#endif
+
 // optimize images memory usage
 pref("image.downscale-during-decode.enabled", true);