Bug 1593843 - part6 : add a static pref to control this feature. r=bryce

`media.geckoview.autoplay.request` is used to control whether we send the play request.
`media.geckoview.autoplay.request.testing` is used to control the request result in testing.

Differential Revision: https://phabricator.services.mozilla.com/D52605

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

dom/media/GVAutoplayPermissionRequest.cpp

@@ -5,6 +5,7 @@
 #include "GVAutoplayPermissionRequest.h"
 
 #include "mozilla/dom/HTMLMediaElement.h"
+#include "mozilla/StaticPrefs_media.h"
 
 namespace mozilla {
 namespace dom {
@@ -20,6 +21,18 @@ static RStatus GetRequestStatus(BrowsingContext* aContext, RType aType) {
              : aContext->GetGVInaudibleAutoplayRequestStatus();
 }
 
+// This is copied from the value of `media.geckoview.autoplay.request.testing`.
+enum class TestRequest : uint32_t {
+  ePromptAsNormal = 0,
+  eAllowAll = 1,
+  eDenyAll = 2,
+  eAllowAudible = 3,
+  eDenyAudible = 4,
+  eAllowInAudible = 5,
+  eDenyInAudible = 6,
+  eLeaveAllPending = 7,
+};
+
 NS_IMPL_CYCLE_COLLECTION_INHERITED(GVAutoplayPermissionRequest,
                                    ContentPermissionRequestBase)
 
@@ -33,9 +46,27 @@ void GVAutoplayPermissionRequest::CreateRequest(nsGlobalWindowInner* aWindow,
   RefPtr<GVAutoplayPermissionRequest> request =
       new GVAutoplayPermissionRequest(aWindow, aContext, aType);
   request->SetRequestStatus(RStatus::ePENDING);
-  request->RequestDelayedTask(
-      aWindow->EventTargetFor(TaskCategory::Other),
-      GVAutoplayPermissionRequest::DelayedTaskType::Request);
+  const TestRequest testingPref = static_cast<TestRequest>(
+      StaticPrefs::media_geckoview_autoplay_request_testing());
+  if (testingPref != TestRequest::ePromptAsNormal) {
+    if (testingPref == TestRequest::eAllowAll ||
+        (testingPref == TestRequest::eAllowAudible &&
+         aType == RType::eAUDIBLE) ||
+        (testingPref == TestRequest::eAllowInAudible &&
+         aType == RType::eINAUDIBLE)) {
+      request->Allow(JS::UndefinedHandleValue);
+    } else if (testingPref == TestRequest::eDenyAll ||
+               (testingPref == TestRequest::eDenyAudible &&
+                aType == RType::eAUDIBLE) ||
+               (testingPref == TestRequest::eDenyInAudible &&
+                aType == RType::eINAUDIBLE)) {
+      request->Cancel();
+    }
+  } else {
+    request->RequestDelayedTask(
+        aWindow->EventTargetFor(TaskCategory::Other),
+        GVAutoplayPermissionRequest::DelayedTaskType::Request);
+  }
 }
 
 GVAutoplayPermissionRequest::GVAutoplayPermissionRequest(
@@ -115,6 +146,10 @@ void GVAutoplayPermissionRequestor::AskForPermissionIfNeeded(
     return;
   }
 
+  if (!StaticPrefs::media_geckoview_autoplay_request()) {
+    return;
+  }
+
   // The request status is stored in top-level browsing context only.
   RefPtr<BrowsingContext> context = aWindow->GetBrowsingContext()->Top();
   if (!HasEverAskForRequest(context, RType::eAUDIBLE)) {

modules/libpref/init/StaticPrefList.yaml

@@ -6442,6 +6442,24 @@
   value: false
   mirror: always
 
+ # If true, then we require explicit approval from the embedding app (ex. Fenix)
+ # on GeckoView to know if we can allow audible, inaudible media or both kinds
+ # of media to autoplay.
+- name: media.geckoview.autoplay.request
+  type: bool
+  value: false
+  mirror: always
+
+ # This is used in testing only, in order to skip the prompting process. This
+ # pref works only when enabling the pref `media.geckoview.autoplay.request`.
+ # 0=prompt as normal, 1=allow all, 2=deny all, 3=allow audible request,
+ # 4=deny audible request, 5=allow inaudible request, 6=deny inaudible request.
+ # 7=leave all requests pending.
+- name: media.geckoview.autoplay.request.testing
+  type: uint32_t
+  value: 0
+  mirror: always
+
 #---------------------------------------------------------------------------
 # Prefs starting with "mousewheel."
 #---------------------------------------------------------------------------

testing/profiles/common/user.js

@@ -65,3 +65,5 @@ user_pref("media.allowed-to-play.enabled", true);
 // Ensure media can always play without delay
 user_pref("media.block-autoplay-until-in-foreground", false);
 user_pref("toolkit.telemetry.coverage.endpoint.base", "http://localhost");
+// Don't ask for a request in testing unless explicitly set this as true.
+user_pref("media.geckoview.autoplay.request", false);