[Autoplay] Add flag to about://flags

Add flag for new unified sound settings UI to about://flags.

BUG=865548

Change-Id: Ie3a3139d9af32bacfe6992708841272c47f4179c
Reviewed-on: https://chromium-review.googlesource.com/1176648Reviewed-by: Tommy Steimel <steimel@chromium.org>
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583677}

chrome/browser/about_flags.cc

@@ -4336,6 +4336,11 @@ const FeatureEntry kFeatureEntries[] = {
                                     kResamplingInputEventsFeatureVariations,
                                     "ResamplingScrollEvents")},
 
+    {"enable-autoplay-unified-sound-settings",
+     flag_descriptions::kEnableAutoplayUnifiedSoundSettingsName,
+     flag_descriptions::kEnableAutoplayUnifiedSoundSettingsDescription,
+     kOsDesktop, FEATURE_VALUE_TYPE(media::kAutoplaySoundSettings)},
+
     // NOTE: Adding a new flag requires adding a corresponding entry to enum
     // "LoginCustomFlags" in tools/metrics/histograms/enums.xml. See "Flag
     // Histograms" in tools/metrics/histograms/README.md (run the

chrome/browser/flag_descriptions.cc

@@ -440,6 +440,11 @@ const char kEnableAutoplayIgnoreWebAudioName[] =
 const char kEnableAutoplayIgnoreWebAudioDescription[] =
     "If enabled, autoplay restrictions will be ignored for WebAudio.";
 
+const char kEnableAutoplayUnifiedSoundSettingsName[] =
+    "Autoplay unified sound settings UI";
+const char kEnableAutoplayUnifiedSoundSettingsDescription[] =
+    "If enabled, shows the new unified autoplay sound settings UI.";
+
 const char kEnableBreakingNewsPushName[] = "Breaking News Push";
 const char kEnableBreakingNewsPushDescription[] =
     "Listen for breaking news content suggestions (e.g. for New Tab Page) "

chrome/browser/flag_descriptions.h

@@ -296,6 +296,9 @@ extern const char kEnableAutofillSendExperimentIdsInPaymentsRPCsDescription[];
 extern const char kEnableAutoplayIgnoreWebAudioName[];
 extern const char kEnableAutoplayIgnoreWebAudioDescription[];
 
+extern const char kEnableAutoplayUnifiedSoundSettingsName[];
+extern const char kEnableAutoplayUnifiedSoundSettingsDescription[];
+
 extern const char kEnableBreakingNewsPushName[];
 extern const char kEnableBreakingNewsPushDescription[];
 

tools/metrics/histograms/enums.xml

@@ -28857,6 +28857,7 @@ from previous Chrome versions.
   <int value="217455219" label="SyncStandaloneTransport:enabled"/>
   <int value="218890378" label="ManualSaving:disabled"/>
   <int value="219117936" label="AllowReaderForAccessibility:enabled"/>
+  <int value="219682005" label="AutoplaySoundSettings:disabled"/>
   <int value="222184258"
       label="AutofillEnforceMinRequiredFieldsForHeuristics:disabled"/>
   <int value="223662457" label="BackgroundLoadingForDownloads:enabled"/>
@@ -29547,6 +29548,7 @@ from previous Chrome versions.
   <int value="1612446645" label="enable-weak-memorycache"/>
   <int value="1612871297" label="WebPayments:disabled"/>
   <int value="1612974229" label="allow-insecure-localhost"/>
+  <int value="1614528057" label="AutoplaySoundSettings:enabled"/>
   <int value="1614596813" label="CloseButtonsInactiveTabs:disabled"/>
   <int value="1615988672" label="GrantNotificationsToDSE:enabled"/>
   <int value="1617187093" label="enable-improved-a2hs"/>