--- a/toolkit/moz.configure
+++ b/toolkit/moz.configure
@@ -339,17 +339,26 @@ def fmp4(value, target, wmf, applemedia)
         return True
 
 set_config('MOZ_FMP4', fmp4)
 set_define('MOZ_FMP4', fmp4)
 add_old_configure_assignment('MOZ_FMP4', fmp4)
 
 # EME Support
 # ==============================================================
-option('--enable-eme', nargs='*', choices=('adobe','widevine',),
+# Widevine is enabled by default in desktop browser builds.
+@depends(build_project, '--help')
+def eme_default(build_project, help):
+    if build_project == 'browser':
+        return 'widevine'
+
+option('--enable-eme',
+       nargs='*',
+       choices=('adobe','widevine',),
+       default=eme_default,
        help='Enable support for Encrypted Media Extensions')
 
 @depends('--enable-eme', fmp4)
 def eme(value, fmp4):
     enabled = bool(value)
     if value.origin == 'default':
         enabled = enabled or fmp4
     if enabled and not fmp4: