Android: Add an option to the feature flag overscroll navigation

This CL modifies the feature flag overscroll navigation so that users
can enable/disable navigation sheet as an option.

Bug: 937946
Change-Id: Id7bf39054d561927be74262331226ce112ef7caf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1694184
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676326}

chrome/android/java/src/org/chromium/chrome/browser/gesturenav/SideSlideLayout.java

@@ -20,6 +20,7 @@ import android.view.animation.Transformation;
 
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.chrome.R;
+import org.chromium.chrome.browser.ChromeFeatureList;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -34,6 +35,8 @@ import java.lang.annotation.RetentionPolicy;
  * and modified accordingly to support horizontal gesture.
  */
 public class SideSlideLayout extends ViewGroup {
+    private static final String NAVIGATION_SHEET_ENABLED_KEY =
+            "overscroll_history_navigation_bottom_sheet";
     // Used to record the UMA histogram Overscroll.* This definition should be
     // in sync with that in content/browser/web_contents/aura/types.h
     // TODO(jinsukkim): Generate java enum from the native header.
@@ -171,6 +174,12 @@ public class SideSlideLayout extends ViewGroup {
         mTotalDragDistance = TARGET_THRESHOLD_DP * density;
     }
 
+    private static boolean isBottomSheetEnabled() {
+        return ChromeFeatureList.getFieldTrialParamByFeatureAsBoolean(
+                ChromeFeatureList.OVERSCROLL_HISTORY_NAVIGATION, NAVIGATION_SHEET_ENABLED_KEY,
+                false);
+    }
+
     /**
      * Set the listener to be notified when the navigation is triggered.
      */

chrome/browser/about_flags.cc

@@ -876,6 +876,12 @@ const FeatureEntry::FeatureVariation
          base::size(kTranslateForceTriggerOnEnglishGeo), nullptr},
         {"(Zero threshold)", kTranslateForceTriggerOnEnglishBackoff,
          base::size(kTranslateForceTriggerOnEnglishBackoff), nullptr}};
+
+const FeatureEntry::FeatureParam kOverscrollHistoryNavigationBottomSheet[] = {
+    {"overscroll_history_navigation_bottom_sheet", "true"}};
+const FeatureEntry::FeatureVariation kOverscrollHistoryNavigationVariations[] =
+    {{"Navigation sheet", kOverscrollHistoryNavigationBottomSheet,
+      base::size(kOverscrollHistoryNavigationBottomSheet), nullptr}};
 #endif  // defined(OS_ANDROID)
 
 #if !defined(OS_ANDROID)
@@ -1559,12 +1565,16 @@ const FeatureEntry kFeatureEntries[] = {
      flag_descriptions::kOverscrollHistoryNavigationName,
      flag_descriptions::kOverscrollHistoryNavigationDescription,
      kOsAura | kOsAndroid,
+#if defined(OS_ANDROID)
+     FEATURE_WITH_PARAMS_VALUE_TYPE(features::kOverscrollHistoryNavigation,
+                                    kOverscrollHistoryNavigationVariations,
+                                    "OverscrollNavigation")},
+#else
      FEATURE_VALUE_TYPE(features::kOverscrollHistoryNavigation)},
-#if !defined(OS_ANDROID)
     {"pull-to-refresh", flag_descriptions::kPullToRefreshName,
      flag_descriptions::kPullToRefreshDescription, kOsAura,
      MULTI_VALUE_TYPE(kPullToRefreshChoices)},
-#endif  // !OS_ANDROID
+#endif  // OS_ANDROID
 #endif  // USE_AURA || OS_ANDROID
     {"enable-touch-drag-drop", flag_descriptions::kTouchDragDropName,
      flag_descriptions::kTouchDragDropDescription, kOsWin | kOsCrOS,