Autoplay: only disable Web Audio autoplay policy when the document user activation policy applies.

This is affecting WebView that has a different autoplay policy but
also would affect any client using a different policy from the default
one.

Bug: 850445
Change-Id: Ifaac3e15c4644c32e540b20e62bb3ee70d9a0b12
Reviewed-on: https://chromium-review.googlesource.com/1102827Reviewed-by: Bo <boliu@chromium.org>
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567753}

android_webview/lib/aw_main_delegate.cc

@@ -170,10 +170,6 @@ bool AwMainDelegate::BasicStartupComplete(int* exit_code) {
   CommandLineHelper::AddDisabledFeature(*cl,
                                         media::kMediaDrmPersistentLicense.name);
 
-  // WebView requires audio autoplay to respect the document autoplay behavior.
-  CommandLineHelper::AddDisabledFeature(*cl,
-                                        media::kAutoplayIgnoreWebAudio.name);
-
   CommandLineHelper::AddEnabledFeature(
       *cl, autofill::features::kAutofillSkipComparingInferredLabels.name);
 

third_party/blink/renderer/modules/webaudio/audio_context.cc

@@ -313,7 +313,15 @@ void AudioContext::NotifySourceNodeStart() {
 }
 
 AutoplayPolicy::Type AudioContext::GetAutoplayPolicy() const {
-  if (RuntimeEnabledFeatures::AutoplayIgnoresWebAudioEnabled()) {
+  Document* document = GetDocument();
+  DCHECK(document);
+
+  auto autoplay_policy =
+      AutoplayPolicy::GetAutoplayPolicyForDocument(*document);
+
+  if (autoplay_policy ==
+          AutoplayPolicy::Type::kDocumentUserActivationRequired &&
+      RuntimeEnabledFeatures::AutoplayIgnoresWebAudioEnabled()) {
 // When ignored, the policy is different on Android compared to Desktop.
 #if defined(OS_ANDROID)
     return AutoplayPolicy::Type::kUserGestureRequired;
@@ -323,9 +331,7 @@ AutoplayPolicy::Type AudioContext::GetAutoplayPolicy() const {
 #endif
   }
 
-  Document* document = GetDocument();
-  DCHECK(document);
-  return AutoplayPolicy::GetAutoplayPolicyForDocument(*document);
+  return autoplay_policy;
 }
 
 bool AudioContext::AreAutoplayRequirementsFulfilled() const {