Restrict AppCache to secure contexts.

Intent to Remove: https://groups.google.com/a/chromium.org/d/msg/blink-dev/ANnafFBhReY/1Xdr53KxBAAJ

Bug: 588931
Change-Id: I6dc296734ea6b1fdf1478bea7a1e80ca8afe38ac
Reviewed-on: https://chromium-review.googlesource.com/1160644
Commit-Queue: Mike West <mkwst@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580506}

chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc

@@ -1112,11 +1112,6 @@ IN_PROC_BROWSER_TEST_F(PageLoadMetricsBrowserTest,
   histogram_tester_.ExpectBucketCount(
       internal::kFeaturesHistogramName,
       static_cast<int32_t>(WebFeature::kDataUriHasOctothorpe), 1);
-  histogram_tester_.ExpectBucketCount(
-      internal::kFeaturesHistogramName,
-      static_cast<int32_t>(
-          WebFeature::kApplicationCacheManifestSelectInsecureOrigin),
-      1);
   histogram_tester_.ExpectBucketCount(
       internal::kFeaturesHistogramName,
       static_cast<int32_t>(WebFeature::kPageVisits), 1);

third_party/WebKit/LayoutTests/http/tests/security/powerfulFeatureRestrictions/old-powerful-features-on-insecure-origin-expected.txt

-CONSOLE WARNING: Application Cache is deprecated in non-secure contexts, and will be restricted to secure contexts in M69, around September 2018. Please consider migrating your application to HTTPS, and eventually shifting over to Service Workers. See https://goo.gl/rStTGz for more details.
+CONSOLE WARNING: Application Cache is restricted to secure contexts. Please consider migrating your application to HTTPS, and eventually shifting over to Service Workers. See https://goo.gl/rStTGz for more details.
 CONSOLE WARNING: line 68: getCurrentPosition() and watchPosition() no longer work on insecure origins. To use this feature, you should consider switching your application to a secure origin, such as HTTPS. See https://goo.gl/rStTGz for more details.
 CONSOLE WARNING: line 87: getUserMedia() no longer works on insecure origins. To use this feature, you should consider switching your application to a secure origin, such as HTTPS. See https://goo.gl/rStTGz for more details.
 CONSOLE WARNING: line 430: The devicemotion event is deprecated on insecure origins, and support will be removed in the future. You should consider switching your application to a secure origin, such as HTTPS. See https://goo.gl/rStTGz for more details.

third_party/blink/renderer/core/frame/deprecation.cc

@@ -341,15 +341,11 @@ DeprecationInfo GetDeprecationInfo(WebFeature feature) {
 
     case WebFeature::kApplicationCacheManifestSelectInsecureOrigin:
     case WebFeature::kApplicationCacheAPIInsecureOrigin:
-      return {
-          "ApplicationCacheAPIInsecureOrigin", kM69,
-          String::Format(
-              "Application Cache is deprecated in non-secure contexts, and "
-              "will be restricted to secure contexts in %s. Please consider "
-              "migrating your application to HTTPS, and eventually shifting "
-              "over to Service Workers. See https://goo.gl/rStTGz for more "
-              "details.",
-              MilestoneString(kM69))};
+      return {"ApplicationCacheAPIInsecureOrigin", kM70,
+              "Application Cache is restricted to secure contexts. Please "
+              "consider migrating your application to HTTPS, and eventually "
+              "shifting over to Service Workers. See https://goo.gl/rStTGz for "
+              "more details."};
 
     case WebFeature::kNotificationInsecureOrigin:
     case WebFeature::kNotificationAPIInsecureOriginIframe:

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1100,7 +1100,7 @@
     },
     {
       name: "RestrictAppCacheToSecureContexts",
-      status: "experimental",
+      status: "stable",
     },
     {
       name: "RestrictCanRequestURLCharacterSet",