Make number of text fragments look up configurable

(cherry picked from commit fa583b9)

Bug: 1450935
Change-Id: Ia574e98c12052505f3558310fc8bd65cf08eee8c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4584414
Reviewed-by: Peter Conn <peconn@chromium.org>
Reviewed-by: Jun Zou <junzou@chromium.org>
Commit-Queue: Tarun Bansal <tbansal@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1153148}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4598674
Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Cr-Commit-Position: refs/branch-heads/5790@{#495}
Cr-Branched-From: 1d71a33-refs/heads/main@{#1148114}

chrome/browser/android/customtabs/text_fragment_lookup_state_tracker.cc

@@ -50,7 +50,7 @@ void TextFragmentLookupStateTracker::LookupTextFragment(
       ExtractAllowedTextDirectives(text_directives);
   // Increment lookup counter.
   lookup_count_ += allowed_text_directives.size();
-  DCHECK_LE(lookup_count_, kMaxNumLookupPerPage);
+  DCHECK_LE(lookup_count_, max_lookups_per_page());
 
   // Create and attach a `TextFinderManager` to the primary page.
   content::Page& page = web_contents()->GetPrimaryPage();
@@ -69,17 +69,17 @@ std::vector<std::string>
 TextFragmentLookupStateTracker::ExtractAllowedTextDirectives(
     const std::vector<std::string>& text_directives) const {
   // Check if the lookup counter exceeds the max number.
-  if (lookup_count_ >= kMaxNumLookupPerPage) {
+  if (lookup_count_ >= max_lookups_per_page()) {
     return {};
   }
 
   // Extract the first allowed number of text directives.
   size_t cur_num = text_directives.size();
-  if (lookup_count_ + cur_num <= kMaxNumLookupPerPage) {
+  if (lookup_count_ + cur_num <= max_lookups_per_page()) {
     return text_directives;
   } else {
     // Throttled.
-    size_t allowed_num = kMaxNumLookupPerPage - lookup_count_;
+    size_t allowed_num = max_lookups_per_page() - lookup_count_;
     return std::vector<std::string>(text_directives.begin(),
                                     text_directives.begin() + allowed_num);
   }
@@ -105,6 +105,12 @@ void TextFragmentLookupStateTracker::PrimaryPageChanged(content::Page& page) {
   lookup_count_ = 0;
 }
 
+size_t TextFragmentLookupStateTracker::max_lookups_per_page() const {
+  return GetFieldTrialParamByFeatureAsInt(
+      chrome::android::kCCTTextFragmentLookupApiEnabled, "max_lookups_per_page",
+      15);
+}
+
 WEB_CONTENTS_USER_DATA_KEY_IMPL(TextFragmentLookupStateTracker);
 
 }  // namespace customtabs

chrome/browser/android/customtabs/text_fragment_lookup_state_tracker.h

@@ -11,8 +11,6 @@
 
 namespace customtabs {
 
-const size_t kMaxNumLookupPerPage = 15;
-
 class TextFragmentLookupStateTracker
     : public content::WebContentsObserver,
       public content::WebContentsUserData<TextFragmentLookupStateTracker> {
@@ -50,6 +48,8 @@ class TextFragmentLookupStateTracker
   // Implements `content::WebContentsObserver`:
   void PrimaryPageChanged(content::Page& page) override;
 
+  size_t max_lookups_per_page() const;
+
   WEB_CONTENTS_USER_DATA_KEY_DECL();
 
   size_t lookup_count_ = 0;