[Overlay] Default-enable the new layout.

This enables the OverlayNewLayout feature for all builds.

We've pushed this to 1% Stable on M79 and the metrics look good, so
default-enabling for M81 (will revert if the experiment has snags).

BUG=929870

Change-Id: Iaa9ba3d0b3712d66db936b8991b5635c3f11aa4a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1993876
Auto-Submit: Donn Denman <donnd@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Donn Denman <donnd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#731848}

chrome/browser/android/chrome_feature_list.cc

@@ -505,7 +505,7 @@ const base::Feature kOmniboxSpareRenderer{"OmniboxSpareRenderer",
                                           base::FEATURE_DISABLED_BY_DEFAULT};
 
 const base::Feature kOverlayNewLayout{"OverlayNewLayout",
-                                      base::FEATURE_DISABLED_BY_DEFAULT};
+                                      base::FEATURE_ENABLED_BY_DEFAULT};
 
 // TODO(rouslan): Remove this.
 const base::Feature kPayWithGoogleV1{"PayWithGoogleV1",

testing/variations/fieldtrial_testing_config.json

@@ -4389,21 +4389,6 @@
             ]
         }
     ],
-    "OverlayNewLayout": [
-        {
-            "platforms": [
-                "android"
-            ],
-            "experiments": [
-                {
-                    "name": "OverlayNewLayout",
-                    "enable_features": [
-                        "OverlayNewLayout"
-                    ]
-                }
-            ]
-        }
-    ],
     "OzoneDrmMojo": [
         {
             "platforms": [