Bug 1158392 - Mark some more webm-video reftests as failing or random on Android. r=kats

Manual testing shows expected rendering of the pages in question. The tests
do not reproduce locally and are tricky to debug on Try. Moreover, most
other reftests in this directory are already marked as failing or random
on Android.

For these reasons, I don't want these failures to block the rollout of
containerless scrolling. Bug 1084564 tracks re-enabling them.

Differential Revision: https://phabricator.services.mozilla.com/D19679

--HG--
extra : moz-landing-system : lando

layout/reftests/webm-video/reftest.list

@@ -24,14 +24,14 @@ fails-if(Android) skip-if(Android&&AndroidVersion=='18') == poster-2.html poster
 random-if(Android) == poster-3.html poster-ref-black140x100.html
 == poster-4.html poster-ref-black140x100.html
 random-if(Android) == poster-5.html poster-ref-black140x100.html
-== poster-6.html poster-ref-black140x100.html
-== poster-7.html poster-ref-red140x100.html
+fails-if(Android) == poster-6.html poster-ref-black140x100.html
+fails-if(Android) == poster-7.html poster-ref-red140x100.html
 fuzzy-if(Android,0-2,0-14000) == poster-8.html poster-ref-black140x100.html
 random == poster-10.html poster-ref-blue125x100.html
 random == poster-11.html poster-ref-blue140x100.html
 random == poster-12.html poster-ref-blue140x100.html
-== poster-13.html poster-ref-blue400x300.html
-== poster-15.html poster-ref-green70x30.html
+random-if(Android) == poster-13.html poster-ref-blue400x300.html
+random-if(Android) == poster-15.html poster-ref-green70x30.html
 random-if(winWidget) random-if(cocoaWidget) skip-if(Android) == bug686957.html bug686957-ref.html # bug 922951 for OS X
 == webm-alpha.html webm-alpha-ref.html