[Android] Added a runtime flag to enable autoplay of muted videos.

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 85a46e06e4d42ce154f059336b6daa7d9abc72ee..ac046242f6a095d0031d42ee04ce6cb68e16901b 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -1896,6 +1896,9 @@ const FeatureEntry kFeatureEntries[] = {
     {"important-sites-in-cbd", IDS_FLAGS_IMPORTANT_SITES_IN_CBD_NAME,
      IDS_FLAGS_IMPORTANT_SITES_IN_CBD_DESCRIPTION, kOsAndroid,
      FEATURE_VALUE_TYPE(chrome::android::kImportantSitesInCBD)},
+    {"enable-video-as-images", IDS_FLAGS_ENABLE_VIDEOS_AS_IMAGES_NAME,
+     IDS_FLAGS_ENABLE_VIDEOS_AS_IMAGES_DESCRIPTION, kOsAndroid,
+     SINGLE_VALUE_TYPE(switches::kEnableVideosAsImages)},
 #endif
     {"enable-pointer-events",  // FLAGS:RECORD_UMA
      IDS_FLAGS_EXPERIMENTAL_POINTER_EVENT_NAME,