Disable media learning features by default

Previously enabled to collect experiment data. We don't mean to ship
this all the way to stable just yet.

Bug: 1048431
Change-Id: I03d05a1588d2064d6f10fba9cf6eb2b1b7d6fc57
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2037071
Auto-Submit: Chrome Cunningham <chcunningham@chromium.org>
Commit-Queue: Frank Liberato <liberato@chromium.org>
Reviewed-by: Frank Liberato <liberato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738079}

media/base/media_switches.cc

@@ -627,12 +627,12 @@ const base::Feature kMediaLearningExperiment{"MediaLearningExperiment",
 // Enables the general purpose media machine learning framework. Adds reporting
 // only; does not change media behavior.
 const base::Feature kMediaLearningFramework{"MediaLearningFramework",
-                                            base::FEATURE_ENABLED_BY_DEFAULT};
+                                            base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Enables the smoothness prediction experiment.  Requires
 // kMediaLearningFramework to be enabled also, else it does nothing.
 const base::Feature kMediaLearningSmoothnessExperiment{
-    "MediaLearningSmoothnessExperiment", base::FEATURE_ENABLED_BY_DEFAULT};
+    "MediaLearningSmoothnessExperiment", base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Enable aggregate power measurement for media playback.
 const base::Feature kMediaPowerExperiment{"MediaPowerExperiment",