Reland "blink: Enable JPEG YUV decoding on TOT"

This is a reland of 08ad21a9

Original change's description:
> blink: Enable JPEG YUV decoding on TOT
> 
> The JPEG YUV decoding experiment has concluded and can now be enabled on
> TOT. This change enables YUV decoding for JPEG images by default and
> removes the field trial testing config.
> 
> Bug: 919627
> Change-Id: Ic3742750af59fa3b4e6dedc2f55424d4a87afcad
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2216712
> Reviewed-by: Steven Holte <holte@chromium.org>
> Reviewed-by: Kentaro Hara <haraken@chromium.org>
> Commit-Queue: Sasha McIntosh <sashamcintosh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#772724}

Bug: 919627
Change-Id: Ib162ea913ab0fdf588206d8ea0560cbbf259cb37
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2386487Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Sasha McIntosh <sashamcintosh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804065}

testing/variations/fieldtrial_testing_config.json

@@ -1707,27 +1707,6 @@
             ]
         }
     ],
-    "DecodeJpegToYuv": [
-        {
-            "platforms": [
-                "android",
-                "android_weblayer",
-                "android_webview",
-                "chromeos",
-                "linux",
-                "mac",
-                "windows"
-            ],
-            "experiments": [
-                {
-                    "name": "Experiment",
-                    "enable_features": [
-                        "DecodeJpeg420ImagesToYUV"
-                    ]
-                }
-            ]
-        }
-    ],
     "DefaultBrowserInfobar": [
         {
             "platforms": [

third_party/blink/common/features.cc

@@ -311,8 +311,8 @@ const char kMixedContentAutoupgradeModeAllPassive[] = "all-passive";
 // Decodes jpeg 4:2:0 formatted images to YUV instead of RGBX and stores in this
 // format in the image decode cache. See crbug.com/919627 for details on the
 // feature.
-const base::Feature kDecodeJpeg420ImagesToYUV{
-    "DecodeJpeg420ImagesToYUV", base::FEATURE_DISABLED_BY_DEFAULT};
+const base::Feature kDecodeJpeg420ImagesToYUV{"DecodeJpeg420ImagesToYUV",
+                                              base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Decodes lossy WebP images to YUV instead of RGBX and stores in this format
 // in the image decode cache. See crbug.com/900264 for details on the feature.