[client hints] Send sec-ch-ua-mobile by default

This is basically Aaron Tagliaboschi's:
https://chromium-review.googlesource.com/c/chromium/src/+/2012902
just with a bit of additional updated of tests.

See https://github.com/WICG/ua-client-hints/issues/15 for rationale.

Change-Id: I6562cf1a78ceb4eff18baf793cb89143782f9b7b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2047410
Commit-Queue: Maksim Orlovich <morlovich@chromium.org>
Reviewed-by: Yoav Weiss <yoavweiss@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741152}

content/browser/client_hints/client_hints.cc

@@ -498,6 +498,10 @@ void AddNavigationRequestClientHintsHeaders(
                 version.empty() ? ua.brand
                                 : base::StringPrintf("%s %s", ua.brand.c_str(),
                                                      version.c_str()));
+    // The `Sec-CH-UA-Mobile client hint was also deemed "low entropy" and can
+    // safely be sent with every request.
+    AddUAHeader(headers, blink::mojom::WebClientHintsType::kUAMobile,
+                ua.mobile ? "?1" : "?0");
 
     if (ShouldAddClientHint(
             web_client_hints, feature_policy, resource_origin,
@@ -522,14 +526,6 @@ void AddNavigationRequestClientHintsHeaders(
       AddUAHeader(headers, blink::mojom::WebClientHintsType::kUAModel,
                   ua.model);
     }
-
-    if (ShouldAddClientHint(
-            web_client_hints, feature_policy, resource_origin,
-            blink::mojom::WebClientHintsType::kUAMobile,
-            blink::mojom::FeaturePolicyFeature::kClientHintUAMobile)) {
-      AddUAHeader(headers, blink::mojom::WebClientHintsType::kUAMobile,
-                  ua.mobile ? "?1" : "?0");
-    }
   }
 
   // Static assert that triggers if a new client hint header is added. If a

third_party/blink/renderer/core/loader/frame_fetch_context.cc

@@ -554,6 +554,15 @@ void FrameFetchContext::AddClientHintsIfNecessary(
         blink::kClientHintsHeaderMapping[static_cast<size_t>(
             mojom::WebClientHintsType::kUA)],
         AddQuotes(result.ToString().Ascii()));
+
+    // We also send Sec-CH-UA-Mobile to all hints. It is a one-bit header
+    // identifying if the browser has opted for a "mobile" experience
+    // Formatted using the "sh-boolean" format from:
+    // https://httpwg.org/http-extensions/draft-ietf-httpbis-header-structure.html#boolean
+    request.SetHttpHeaderField(
+        blink::kClientHintsHeaderMapping[static_cast<size_t>(
+            mojom::WebClientHintsType::kUAMobile)],
+        ua.mobile ? "?1" : "?0");
   }
 
   // If the frame is detached, then don't send any hints other than UA.
@@ -755,19 +764,6 @@ void FrameFetchContext::AddClientHintsIfNecessary(
             mojom::WebClientHintsType::kUAModel)],
         AddQuotes(ua.model));
   }
-
-  if ((can_always_send_hints ||
-       (RuntimeEnabledFeatures::FeaturePolicyForClientHintsEnabled() &&
-        policy->IsFeatureEnabledForOrigin(
-            mojom::blink::FeaturePolicyFeature::kClientHintUAMobile,
-            resource_origin))) &&
-      ShouldSendClientHint(mojom::WebClientHintsType::kUAMobile,
-                           hints_preferences, enabled_hints)) {
-    request.SetHttpHeaderField(
-        blink::kClientHintsHeaderMapping[static_cast<size_t>(
-            mojom::WebClientHintsType::kUAMobile)],
-        ua.mobile ? "?1" : "?0");
-  }
 }
 
 void FrameFetchContext::PopulateResourceRequest(

third_party/blink/web_tests/external/wpt/client-hints/accept-ch-feature-policy.sub.https.html

@@ -56,7 +56,6 @@ promise_test(t => {
     assert_false(r.headers.has("rtt-received"), "rtt-received");
     assert_false(r.headers.has("downlink-received"), "downlink-received");
     assert_false(r.headers.has("ect-received"), "ect-received");
-    assert_false(r.headers.has("mobile-received"), "mobile-received");
   });
 }, "Cross-Origin Accept-CH header test");
 

third_party/blink/web_tests/external/wpt/service-workers/service-worker/fetch-request-xhr.https-expected.txt

 This is a testharness.js-based test.
 PASS initialize global state
-FAIL event.request has the expected headers for same-origin GET. promise_test: Unhandled rejection with value: object "Error: assert_array_equals: event.request has the expected headers for same-origin GET. lengths differ, expected array ["accept"] length 1, got ["accept", "sec-ch-ua", "user-agent"] length 3"
-FAIL event.request has the expected headers for same-origin POST. promise_test: Unhandled rejection with value: object "Error: assert_array_equals: event.request has the expected headers for same-origin POST. lengths differ, expected array ["accept", "content-type"] length 2, got ["accept", "content-type", "sec-ch-ua", "user-agent"] length 4"
-FAIL event.request has the expected headers for cross-origin GET. promise_test: Unhandled rejection with value: object "Error: assert_array_equals: event.request has the expected headers for cross-origin GET. lengths differ, expected array ["accept"] length 1, got ["accept", "sec-ch-ua", "user-agent"] length 3"
-FAIL event.request has the expected headers for cross-origin POST. promise_test: Unhandled rejection with value: object "Error: assert_array_equals: event.request has the expected headers for cross-origin POST. lengths differ, expected array ["accept", "content-type"] length 2, got ["accept", "content-type", "sec-ch-ua", "user-agent"] length 4"
+FAIL event.request has the expected headers for same-origin GET. promise_test: Unhandled rejection with value: object "Error: assert_array_equals: event.request has the expected headers for same-origin GET. lengths differ, expected array ["accept"] length 1, got ["accept", "sec-ch-ua", "sec-ch-ua-mobile", "user-agent"] length 4"
+FAIL event.request has the expected headers for same-origin POST. promise_test: Unhandled rejection with value: object "Error: assert_array_equals: event.request has the expected headers for same-origin POST. lengths differ, expected array ["accept", "content-type"] length 2, got ["accept", "content-type", "sec-ch-ua", "sec-ch-ua-mobile", "user-agent"] length 5"
+FAIL event.request has the expected headers for cross-origin GET. promise_test: Unhandled rejection with value: object "Error: assert_array_equals: event.request has the expected headers for cross-origin GET. lengths differ, expected array ["accept"] length 1, got ["accept", "sec-ch-ua", "sec-ch-ua-mobile", "user-agent"] length 4"
+FAIL event.request has the expected headers for cross-origin POST. promise_test: Unhandled rejection with value: object "Error: assert_array_equals: event.request has the expected headers for cross-origin POST. lengths differ, expected array ["accept", "content-type"] length 2, got ["accept", "content-type", "sec-ch-ua", "sec-ch-ua-mobile", "user-agent"] length 5"
 PASS FetchEvent#request.body contains XHR request data (string)
 PASS FetchEvent#request.body contains XHR request data (blob)
 PASS FetchEvent#request.method is set to XHR method

third_party/blink/web_tests/http/tests/navigation/form-targets-cross-site-frame-get-expected.txt

@@ -15,6 +15,7 @@ HTTP_CONNECTION = keep-alive
 HTTP_HOST = localhost:8080
 HTTP_REFERER = http://127.0.0.1:8000/navigation/form-targets-cross-site-frame-get.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = iframe
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = cross-site

third_party/blink/web_tests/http/tests/navigation/form-targets-cross-site-frame-no-referrer-expected.txt

@@ -16,6 +16,7 @@ HTTP_CONNECTION = keep-alive
 HTTP_HOST = localhost:8080
 HTTP_ORIGIN = null
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = iframe
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = cross-site

third_party/blink/web_tests/http/tests/navigation/form-targets-cross-site-frame-post-expected.txt

@@ -17,6 +17,7 @@ HTTP_HOST = localhost:8080
 HTTP_ORIGIN = http://127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/navigation/form-targets-cross-site-frame-post.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = iframe
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = cross-site

third_party/blink/web_tests/http/tests/navigation/form-with-enctype-targets-cross-site-frame-expected.txt

@@ -17,6 +17,7 @@ HTTP_HOST = localhost:8080
 HTTP_ORIGIN = http://127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/navigation/form-with-enctype-targets-cross-site-frame.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = iframe
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = cross-site

third_party/blink/web_tests/http/tests/navigation/post-basic-expected.txt

@@ -13,6 +13,7 @@ HTTP_HOST = 127.0.0.1:8000
 HTTP_ORIGIN = http://127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/navigation/resources/page-that-posts.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = document
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/navigation/post-frames-expected.txt

@@ -18,6 +18,7 @@ HTTP_HOST = 127.0.0.1:8000
 HTTP_ORIGIN = http://127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/navigation/resources/page-that-posts.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = iframe
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/navigation/post-frames-goback1-expected.txt

@@ -17,6 +17,7 @@ HTTP_HOST = 127.0.0.1:8000
 HTTP_ORIGIN = http://127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/navigation/post-frames-goback1.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = iframe
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/navigation/post-goback1-expected.txt

@@ -13,6 +13,7 @@ HTTP_HOST = 127.0.0.1:8000
 HTTP_ORIGIN = http://127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/navigation/resources/page-that-posts.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = document
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/navigation/rename-subframe-goback-expected.txt

@@ -21,6 +21,7 @@ HTTP_HOST = 127.0.0.1:8000
 HTTP_ORIGIN = http://127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/navigation/resources/page-that-posts.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = iframe
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/security/contentSecurityPolicy/1.1/form-action-leak-path-on-redirect-expected.txt

@@ -9,6 +9,7 @@ HTTP_CONNECTION = keep-alive
 HTTP_HOST = 127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/security/contentSecurityPolicy/1.1/form-action-leak-path-on-redirect.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = document
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/security/contentSecurityPolicy/1.1/form-action-src-allowed-expected.txt

@@ -12,6 +12,7 @@ HTTP_HOST = 127.0.0.1:8000
 HTTP_ORIGIN = http://127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/security/contentSecurityPolicy/1.1/form-action-src-allowed.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = document
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/security/contentSecurityPolicy/1.1/form-action-src-allowed-with-redirect-expected.txt

@@ -9,6 +9,7 @@ HTTP_CONNECTION = keep-alive
 HTTP_HOST = 127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/security/contentSecurityPolicy/1.1/form-action-src-allowed-with-redirect.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = document
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/security/contentSecurityPolicy/1.1/form-action-src-default-ignored-expected.txt

@@ -12,6 +12,7 @@ HTTP_HOST = 127.0.0.1:8000
 HTTP_ORIGIN = http://127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/security/contentSecurityPolicy/1.1/form-action-src-default-ignored.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = document
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/security/contentSecurityPolicy/1.1/form-action-src-default-ignored-with-redirect-expected.txt

@@ -9,6 +9,7 @@ HTTP_CONNECTION = keep-alive
 HTTP_HOST = 127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/security/contentSecurityPolicy/1.1/form-action-src-default-ignored-with-redirect.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = document
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/security/contentSecurityPolicy/1.1/form-action-src-get-allowed-expected.txt

@@ -10,6 +10,7 @@ HTTP_CONNECTION = keep-alive
 HTTP_HOST = 127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/security/contentSecurityPolicy/1.1/form-action-src-get-allowed.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = document
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/security/contentSecurityPolicy/1.1/form-action-src-get-allowed-with-redirect-expected.txt

@@ -9,6 +9,7 @@ HTTP_CONNECTION = keep-alive
 HTTP_HOST = 127.0.0.1:8000
 HTTP_REFERER = http://127.0.0.1:8000/security/contentSecurityPolicy/1.1/form-action-src-get-allowed-with-redirect.html
 HTTP_SEC_CH_UA = content_shell 99
+HTTP_SEC_CH_UA_MOBILE = ?0
 HTTP_SEC_FETCH_DEST = document
 HTTP_SEC_FETCH_MODE = navigate
 HTTP_SEC_FETCH_SITE = same-origin

third_party/blink/web_tests/http/tests/serviceworker/fetch-event-headers.html

@@ -31,7 +31,8 @@ promise_test(function(t) {
           header_names.sort();
           assert_array_equals(
             header_names,
-            ["accept", "sec-ch-ua", "upgrade-insecure-requests", "user-agent"],
+            ["accept", "sec-ch-ua", "sec-ch-ua-mobile",
+             "upgrade-insecure-requests", "user-agent"],
             'event.request has the expected headers.');
 
           return service_worker_unregister_and_done(t, scope);