[WebLayer] Move SUBRESOURCE_FILTER feature to //components/subresource_filter

This CL moves the Java-side definition of the
kSafeBrowsingSubresourceFilter Feature from ChromeFeatureList to a new
SubresourceFilterFeatureList class that lives in
//components/subresource_filter/java. This will allow non-Chrome
embedders to query the status of the Feature from Java.

Bug: 1058597
Change-Id: If9c618216110c1e005e645a0351ee79577211844
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2095860
Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: Charlie Harrison <csharrison@chromium.org>
Cr-Commit-Position: refs/heads/master@{#749402}

chrome/android/BUILD.gn

@@ -331,6 +331,7 @@ android_library("chrome_java") {
     "//components/signin/core/browser/android:java",
     "//components/signin/public/android:java",
     "//components/spellcheck/browser/android:java",
+    "//components/subresource_filter/android:java",
     "//components/sync/android:sync_java",
     "//components/sync/protocol:protocol_java",
     "//components/url_formatter/android:url_formatter_java",

chrome/android/DEPS

@@ -24,6 +24,7 @@ include_rules = [
   "+components/signin/core/browser/android",
   "+components/signin/public/android",
   "+components/spellcheck/browser",
+  "+components/subresource_filter/android",
   "+components/viz/common/java",
   "+jni",
   "+media/base/android/java",

chrome/android/java/src/org/chromium/chrome/browser/site_settings/SiteSettingsCategory.java

@@ -28,6 +28,7 @@ import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.flags.ChromeFeatureList;
 import org.chromium.components.content_settings.ContentSettingsType;
+import org.chromium.components.subresource_filter.SubresourceFilterFeatureList;
 import org.chromium.ui.text.SpanApplier;
 import org.chromium.ui.text.SpanApplier.SpanInfo;
 
@@ -274,7 +275,8 @@ public class SiteSettingsCategory {
      * Returns whether the Ads category is enabled via an experiment flag.
      */
     public static boolean adsCategoryEnabled() {
-        return ChromeFeatureList.isEnabled(ChromeFeatureList.SUBRESOURCE_FILTER);
+        return SubresourceFilterFeatureList.isEnabled(
+                SubresourceFilterFeatureList.SUBRESOURCE_FILTER);
     }
 
     /**

chrome/browser/BUILD.gn

@@ -3014,6 +3014,7 @@ jumbo_static_library("browser") {
       "//components/security_state/content/android",
       "//components/send_tab_to_self",
       "//components/signin/internal/identity_manager",  # cf android/signin/DEPS
+      "//components/subresource_filter/android",
       "//components/viz/common",
       "//media/mojo/clients",
       "//rlz:rlz_utils",

chrome/browser/flags/android/java/src/org/chromium/chrome/browser/flags/ChromeFeatureList.java

@@ -389,7 +389,6 @@ public abstract class ChromeFeatureList {
     public static final String START_SURFACE_ANDROID = "StartSurfaceAndroid";
     public static final String STRICT_HAS_ENROLLED_AUTOFILL_INSTRUMENT =
             "StrictHasEnrolledAutofillInstrument";
-    public static final String SUBRESOURCE_FILTER = "SubresourceFilter";
     public static final String SWAP_PIXEL_FORMAT_TO_FIX_CONVERT_FROM_TRANSLUCENT =
             "SwapPixelFormatToFixConvertFromTranslucent";
     public static final String SYNC_USE_SESSIONS_UNREGISTER_DELAY =

components/subresource_filter/android/BUILD.gn

+# Copyright 2020 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/android/rules.gni")
+
+generate_jni("subresource_filter_jni_headers") {
+  sources = [ "java/src/org/chromium/components/subresource_filter/SubresourceFilterFeatureList.java" ]
+}
+
+android_library("java") {
+  sources = [ "java/src/org/chromium/components/subresource_filter/SubresourceFilterFeatureList.java" ]
+  deps = [
+    ":subresource_filter_jni_headers",
+    "//base:base_java",
+    "//base:jni_java",
+  ]
+  annotation_processor_deps = [ "//base/android/jni_generator:jni_processor" ]
+}
+
+source_set("android") {
+  sources = [ "subresource_filter_feature_list.cc" ]
+  deps = [
+    ":subresource_filter_jni_headers",
+    "//base",
+    "//components/subresource_filter/core/browser",
+  ]
+}

components/subresource_filter/android/java/src/org/chromium/components/subresource_filter/SubresourceFilterFeatureList.java

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.components.subresource_filter;
+
+import org.chromium.base.annotations.JNINamespace;
+import org.chromium.base.annotations.MainDex;
+import org.chromium.base.annotations.NativeMethods;
+import org.chromium.base.library_loader.LibraryLoader;
+
+/**
+ * Provides an API for querying the status of subresource_filter component Features.
+ */
+// TODO(crbug.com/1060097): Remove/update this once a generalized FeatureList exists.
+@JNINamespace("subresource_filter")
+@MainDex
+public class SubresourceFilterFeatureList {
+    public static final String SUBRESOURCE_FILTER = "SubresourceFilter";
+
+    private SubresourceFilterFeatureList() {}
+
+    /**
+     * Returns whether the specified feature is enabled or not.
+     *
+     * Note: Features queried through this API must be added to the array
+     * |kFeaturesExposedToJava| in
+     * //components/subresource_filter/core/browser/subresource_filter_feature_list.cc.
+     *
+     * @param featureName The name of the feature to query.
+     * @return Whether the feature is enabled or not.
+     */
+    public static boolean isEnabled(String featureName) {
+        assert isNativeInitialized();
+        return SubresourceFilterFeatureListJni.get().isEnabled(featureName);
+    }
+
+    /**
+     * @return Whether the native FeatureList is initialized or not.
+     */
+    private static boolean isNativeInitialized() {
+        if (!LibraryLoader.getInstance().isInitialized()) return false;
+        // Even if the native library is loaded, the C++ FeatureList might not be initialized yet.
+        // In that case, accessing it will not immediately fail, but instead cause a crash later
+        // when it is initialized. Return whether the native FeatureList has been initialized,
+        // so the return value can be tested, or asserted for a more actionable stack trace
+        // on failure.
+        //
+        // The FeatureList is however guaranteed to be initialized by the time
+        // AsyncInitializationActivity#finishNativeInitialization is called.
+        return SubresourceFilterFeatureListJni.get().isInitialized();
+    }
+
+    @NativeMethods
+    interface Natives {
+        boolean isInitialized();
+        boolean isEnabled(String featureName);
+    }
+}

components/subresource_filter/android/subresource_filter_feature_list.cc

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/android/jni_string.h"
+#include "base/feature_list.h"
+#include "base/stl_util.h"
+#include "components/subresource_filter/android/subresource_filter_jni_headers/SubresourceFilterFeatureList_jni.h"
+#include "components/subresource_filter/core/browser/subresource_filter_features.h"
+
+using base::android::ConvertJavaStringToUTF8;
+using base::android::JavaParamRef;
+
+namespace subresource_filter {
+
+namespace {
+
+// Array of features exposed through the Java ContentFeatureList API. Entries in
+// this array may either refer to features defined in the header of this file or
+// in other locations in the code base (e.g. content_features.h).
+const base::Feature* kFeaturesExposedToJava[] = {
+    &kSafeBrowsingSubresourceFilter,
+};
+
+// TODO(crbug.com/1060097): Removethis once a generalized FeatureList exists.
+const base::Feature* FindFeatureExposedToJava(const std::string& feature_name) {
+  for (size_t i = 0; i < base::size(kFeaturesExposedToJava); ++i) {
+    if (kFeaturesExposedToJava[i]->name == feature_name)
+      return kFeaturesExposedToJava[i];
+  }
+  NOTREACHED() << "Queried feature not found in SubresourceFilterFeatureList: "
+               << feature_name;
+  return nullptr;
+}
+
+}  // namespace
+
+static jboolean JNI_SubresourceFilterFeatureList_IsInitialized(JNIEnv* env) {
+  return !!base::FeatureList::GetInstance();
+}
+
+static jboolean JNI_SubresourceFilterFeatureList_IsEnabled(
+    JNIEnv* env,
+    const JavaParamRef<jstring>& jfeature_name) {
+  const base::Feature* feature =
+      FindFeatureExposedToJava(ConvertJavaStringToUTF8(env, jfeature_name));
+  return base::FeatureList::IsEnabled(*feature);
+}
+
+}  // namespace subresource_filter