[SH iOS] Add flag for blocklist and hook into edit menu

This CL hooks the new Disabled Sites code in components into the iOS
Shared Highlighting flow. It also adds a new flag which is used in the
process.

Other platforms can reuse the same flag, but it is not yet exposed via
chrome://flags on those platforms and would need to be added.

Bug: 1157981
Change-Id: I9d84fc4c04fe06fd8e806a98b9ff57bd3f743667
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2626207
Commit-Queue: Tommy Martino <tmartino@chromium.org>
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Auto-Submit: Tommy Martino <tmartino@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Reviewed-by: Sebastien Lalancette <seblalancette@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843165}

chrome/browser/flag-metadata.json

@@ -4438,6 +4438,11 @@
     "owners": ["tmartino"],
     "expiry_milestone": 90
   },
+  {
+    "name": "shared-highlighting-use-blocklist",
+    "owners": ["tmartino"],
+    "expiry_milestone": 91
+  },
   {
     "name": "sharing-device-expiration",
     "owners": [ "//chrome/browser/sharing/OWNERS" ],

components/shared_highlighting/core/common/BUILD.gn

@@ -6,6 +6,8 @@ static_library("common") {
   sources = [
     "disabled_sites.cc",
     "disabled_sites.h",
+    "shared_highlighting_features.cc",
+    "shared_highlighting_features.h",
     "shared_highlighting_metrics.cc",
     "shared_highlighting_metrics.h",
     "text_fragment.cc",

components/shared_highlighting/core/common/disabled_sites.cc

@@ -4,6 +4,8 @@
 
 #include "components/shared_highlighting/core/common/disabled_sites.h"
 
+#include "base/feature_list.h"
+#include "components/shared_highlighting/core/common/shared_highlighting_features.h"
 #include "third_party/re2/src/re2/re2.h"
 
 #include <map>
@@ -12,19 +14,22 @@
 namespace shared_highlighting {
 
 bool ShouldOfferLinkToText(const GURL& url) {
-  // If a URL's host matches a key in this map, then the path will be tested
-  // against the RE stored in the value. For example, {"foo.com", ".*"} means
-  // any page on the foo.com domain.
-  const static std::map<std::string, std::string> kBlocklist = {
-      {"youtube.com", ".*"},
-      // TODO(crbug.com/1157981): special case this to cover other Google TLDs
-      {"google.com", "^\\/amp\\/.*"}};
+  if (base::FeatureList::IsEnabled(kSharedHighlightingUseBlocklist)) {
+    // If a URL's host matches a key in this map, then the path will be tested
+    // against the RE stored in the value. For example, {"foo.com", ".*"} means
+    // any page on the foo.com domain.
+    const static std::map<std::string, std::string> kBlocklist = {
+        {"youtube.com", ".*"},
+        // TODO(crbug.com/1157981): special case this to cover other Google TLDs
+        {"google.com", "^\\/amp\\/.*"}};
 
-  const std::string domain =
-      url.host().compare(0, 4, "www.") == 0 ? url.host().substr(4) : url.host();
-  auto it = kBlocklist.find(domain);
-  if (it != kBlocklist.end()) {
-    return !re2::RE2::FullMatch(url.path(), it->second);
+    const std::string domain = url.host().compare(0, 4, "www.") == 0
+                                   ? url.host().substr(4)
+                                   : url.host();
+    auto it = kBlocklist.find(domain);
+    if (it != kBlocklist.end()) {
+      return !re2::RE2::FullMatch(url.path(), it->second);
+    }
   }
   return true;
 }

components/shared_highlighting/core/common/disabled_sites_unittest.cc

@@ -4,6 +4,8 @@
 
 #include "components/shared_highlighting/core/common/disabled_sites.h"
 
+#include "base/test/scoped_feature_list.h"
+#include "components/shared_highlighting/core/common/shared_highlighting_features.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
@@ -39,5 +41,14 @@ TEST(DisabledSitesTest, NonMatchingHost) {
   EXPECT_TRUE(ShouldOfferLinkToText(GURL("https://www.example.com")));
 }
 
+TEST(DisabledSitesTest, FeatureDisabled) {
+  base::test::ScopedFeatureList feature;
+  feature.InitAndDisableFeature(kSharedHighlightingUseBlocklist);
+
+  EXPECT_TRUE(ShouldOfferLinkToText(GURL("https://www.youtube.com")));
+  EXPECT_TRUE(ShouldOfferLinkToText(GURL("https://www.google.com/amp/")));
+  EXPECT_TRUE(ShouldOfferLinkToText(GURL("https://www.example.com")));
+}
+
 }  // namespace
 }  // namespace shared_highlighting

components/shared_highlighting/core/common/shared_highlighting_features.cc

+// Copyright 2021 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 "components/shared_highlighting/core/common/shared_highlighting_features.h"
+
+#include "base/feature_list.h"
+
+namespace shared_highlighting {
+
+const base::Feature kSharedHighlightingUseBlocklist{
+    "SharedHighlightingUseBlocklist", base::FEATURE_ENABLED_BY_DEFAULT};
+
+}  // namespace shared_highlighting

components/shared_highlighting/core/common/shared_highlighting_features.h

+// Copyright 2021 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.
+
+#ifndef COMPONENTS_SHARED_HIGHLIGHTING_CORE_COMMON_SHARED_HIGHLIGHTING_FEATURES_H_
+#define COMPONENTS_SHARED_HIGHLIGHTING_CORE_COMMON_SHARED_HIGHLIGHTING_FEATURES_H_
+
+namespace base {
+struct Feature;
+}
+
+namespace shared_highlighting {
+
+// If enabled, a blocklist will disable link generation on certain pages where
+// the feature is unlikely to work correctly.
+extern const base::Feature kSharedHighlightingUseBlocklist;
+
+}  // namespace shared_highlighting
+
+#endif  // COMPONENTS_SHARED_HIGHLIGHTING_CORE_COMMON_SHARED_HIGHLIGHTING_FEATURES_H_

ios/chrome/browser/DEPS

@@ -84,6 +84,7 @@ include_rules = [
   "+components/services/patch",
   "+components/services/unzip",
   "+components/sessions",
+  "+components/shared_highlighting",
   "+components/signin/core/browser",
   "+components/signin/public",
   "+components/signin/ios/browser",

ios/chrome/browser/flags/BUILD.gn

@@ -35,6 +35,7 @@ source_set("flags") {
     "//components/search_provider_logos",
     "//components/security_state/core",
     "//components/send_tab_to_self",
+    "//components/shared_highlighting/core/common",
     "//components/signin/core/browser",
     "//components/signin/ios/browser",
     "//components/signin/public/base",

ios/chrome/browser/flags/about_flags.mm

@@ -45,6 +45,7 @@
 #include "components/policy/policy_constants.h"
 #include "components/security_state/core/features.h"
 #include "components/send_tab_to_self/features.h"
+#include "components/shared_highlighting/core/common/shared_highlighting_features.h"
 #include "components/signin/core/browser/account_reconcilor.h"
 #include "components/signin/ios/browser/features.h"
 #include "components/signin/public/base/account_consistency_method.h"
@@ -598,6 +599,11 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
      flag_descriptions::kOmniboxNewImplementationName,
      flag_descriptions::kOmniboxNewImplementationDescription, flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(kIOSNewOmniboxImplementation)},
+    {"shared-highlighting-use-blocklist",
+     flag_descriptions::kSharedHighlightingUseBlocklistIOSName,
+     flag_descriptions::kSharedHighlightingUseBlocklistIOSDescription,
+     flags_ui::kOsIos,
+     FEATURE_VALUE_TYPE(shared_highlighting::kSharedHighlightingUseBlocklist)},
 };
 
 bool SkipConditionalFeatureEntry(const flags_ui::FeatureEntry& entry) {

ios/chrome/browser/flags/ios_chrome_flag_descriptions.cc

@@ -259,6 +259,14 @@ const char kIOSSharedHighlightingColorChangeDescription[] =
     "Changes the Shared Highlighting color of the text fragment"
     "away from the default yellow in iOS. Works with #scroll-to-text-ios flag.";
 
+const char kSharedHighlightingUseBlocklistIOSName[] =
+    "Shared Highlighting blocklist";
+const char kSharedHighlightingUseBlocklistIOSDescription[] =
+    "Uses a blocklist to disable Shared Highlighting link generation on "
+    "certain sites where personalized or dynamic content or other technical "
+    "restrictions make it unlikely that a URL can be generated and actually "
+    "work when shared.";
+
 const char kLocationPermissionsPromptName[] =
     "Location Permisssions Prompt Experiment";
 const char kLocationPermissionsPromptDescription[] =

ios/chrome/browser/flags/ios_chrome_flag_descriptions.h

@@ -334,6 +334,11 @@ extern const char kSettingsRefreshDescription[];
 extern const char kSharedHighlightingIOSName[];
 extern const char kSharedHighlightingIOSDescription[];
 
+// Title and description for the flag to use a sites blocklist when generating
+// URLs for Shared Highlighting (Link to Text).
+extern const char kSharedHighlightingUseBlocklistIOSName[];
+extern const char kSharedHighlightingUseBlocklistIOSDescription[];
+
 // Title and description for the flag to enable annotating web forms with
 // Autofill field type predictions as placeholder.
 extern const char kShowAutofillTypePredictionsName[];

ios/chrome/browser/link_to_text/link_to_text_tab_helper.mm

@@ -8,6 +8,7 @@
 #import "base/optional.h"
 #import "base/timer/elapsed_timer.h"
 #import "base/values.h"
+#import "components/shared_highlighting/core/common/disabled_sites.h"
 #import "ios/chrome/browser/link_to_text/link_to_text_constants.h"
 #import "ios/web/public/js_messaging/web_frame.h"
 #import "ios/web/public/js_messaging/web_frames_manager.h"
@@ -40,7 +41,11 @@ void LinkToTextTabHelper::CreateForWebState(web::WebState* web_state) {
 }
 
 bool LinkToTextTabHelper::ShouldOffer() {
-  // TODO(crbug.com/1134708): add more checks, like text only.
+  if (!shared_highlighting::ShouldOfferLinkToText(
+          web_state_->GetLastCommittedURL())) {
+    return false;
+  }
+
   web::WebFrame* main_frame =
       web_state_->GetWebFramesManager()->GetMainWebFrame();
   return web_state_->ContentIsHTML() && main_frame &&