Add a WebView experiment flag for PrefetchRedirects.

This is a soft requirement for a Finch rollout that includes WebView.
This is made easier if we migrate the feature declaration to
content_features.h, which is automatically processed into generated Java
code.

Bug: 1374389
Change-Id: I601bf782bb94f2ca0f14347437c20d8d8f800195
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5177811
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Reviewed-by: Adithya Srinivasan <adithyas@chromium.org>
Auto-Submit: Jeremy Roman <jbroman@chromium.org>
Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1244283}

android_webview/java/src/org/chromium/android_webview/common/ProductionSupportedFlagList.java

@@ -665,8 +665,9 @@ public final class ProductionSupportedFlagList {
                 "Enables showing the cancel dialog by calling preventDefault() "
                         + "on beforeunload event."),
         Flag.baseFeature(
-            BlinkFeatures.CLOSE_WATCHER,
+                BlinkFeatures.CLOSE_WATCHER,
-            "Enables the CloseWatcher JS API and integrates behavior with dialog and popover elements."),
+                "Enables the CloseWatcher JS API and integrates behavior with dialog and popover"
+                        + " elements."),
         Flag.baseFeature(
                 ContentFeatures.QUEUE_NAVIGATIONS_WHILE_WAITING_FOR_COMMIT,
                 "If enabled, allows navigations to be queued when there is "
@@ -697,6 +698,9 @@ public final class ProductionSupportedFlagList {
         Flag.baseFeature(
                 ContentFeatures.PREFETCH_NEW_LIMITS,
                 "Enables new limits policy for SpeculationRules Prefetch."),
+        Flag.baseFeature(
+                ContentFeatures.PREFETCH_REDIRECTS,
+                "Enables following redirects during speculation rules prefetch."),
         Flag.baseFeature(
                 BlinkFeatures.FORM_CONTROLS_VERTICAL_WRITING_MODE_SUPPORT,
                 "Enables support for CSS vertical writing mode on non-text-based form"

content/browser/preloading/prefetch/prefetch_container_unittest.cc

@@ -17,6 +17,7 @@
 #include "content/public/browser/global_routing_id.h"
 #include "content/public/browser/storage_partition.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/common/content_features.h"
 #include "content/public/test/test_renderer_host.h"
 #include "mojo/public/cpp/bindings/remote.h"
 #include "mojo/public/cpp/system/string_data_source.h"

content/browser/preloading/prefetch/prefetch_features.cc

@@ -11,10 +11,6 @@ BASE_FEATURE(kPrefetchUseContentRefactor,
              "PrefetchUseContentRefactor",
              base::FEATURE_ENABLED_BY_DEFAULT);
 
-BASE_FEATURE(kPrefetchRedirects,
-             "PrefetchRedirects",
-             base::FEATURE_DISABLED_BY_DEFAULT);
-
 BASE_FEATURE(kPrefetchReusable,
              "PrefetchReusable",
              base::FEATURE_DISABLED_BY_DEFAULT);

content/browser/preloading/prefetch/prefetch_features.h

@@ -16,9 +16,6 @@ namespace features {
 // chrome/browser/preloadingprefetch/prefetch_proxy/.
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kPrefetchUseContentRefactor);
 
-// IF enabled, then redirects will be followed when prefetching.
-CONTENT_EXPORT BASE_DECLARE_FEATURE(kPrefetchRedirects);
-
 // If enabled, PrefetchContainer can be used for more than one navigation.
 // https://crbug.com/1449360
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kPrefetchReusable);

content/public/common/content_features.cc

@@ -682,6 +682,11 @@ BASE_FEATURE(kPrefetchNewLimits,
              "PrefetchNewLimits",
              base::FEATURE_ENABLED_BY_DEFAULT);
 
+// If enabled, then redirects will be followed when prefetching.
+BASE_FEATURE(kPrefetchRedirects,
+             "PrefetchRedirects",
+             base::FEATURE_DISABLED_BY_DEFAULT);
+
 // Enables exposure of ads APIs in the renderer: Attribution Reporting,
 // FLEDGE, Topics, along with a number of other features actively in development
 // within these APIs.

content/public/common/content_features.h

@@ -168,6 +168,7 @@ CONTENT_EXPORT BASE_DECLARE_FEATURE(kPepperCrossOriginRedirectRestriction);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kPermissionElement);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kPersistentOriginTrials);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kPrefetchNewLimits);
+CONTENT_EXPORT BASE_DECLARE_FEATURE(kPrefetchRedirects);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kPrivacySandboxAdsAPIsOverride);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kPrivateNetworkAccessForNavigations);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kPrivateNetworkAccessForWorkers);