Backed out changeset 95324d36ded5 (Bug 1518405) for causing performance regressions.

modules/libpref/init/all.js

@@ -958,8 +958,7 @@ pref("gfx.webrender.debug.show-overdraw", false);
 pref("gfx.webrender.debug.slow-frame-indicator", false);
 pref("gfx.webrender.dl.dump-parent", false);
 pref("gfx.webrender.dl.dump-content", false);
-
-pref("gfx.webrender.picture-caching", true);
+pref("gfx.webrender.picture-caching", false);
 
 #ifdef EARLY_BETA_OR_EARLIER
 pref("performance.adjust_to_machine", true);