[ios] Remove kBrowserContainerKeepsContentView feature flag.

This feature was dropped in lieu of the KeepRenderProcessAlive flag.

TEST=Does not regress any of the WKWebView hidden test cases.

Bug: 943569, 930123
Change-Id: Ia6ab0e83e808477d6dbc7498607036ac05a31899
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2094468Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Reviewed-by: edchin <edchin@chromium.org>
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Auto-Submit: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748397}

ios/chrome/browser/flags/about_flags.mm

@@ -419,10 +419,6 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
     {"settings-refresh", flag_descriptions::kSettingsRefreshName,
      flag_descriptions::kSettingsRefreshDescription, flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(kSettingsRefresh)},
-    {"browser-container-keeps-content-view",
-     flag_descriptions::kBrowserContainerKeepsContentViewName,
-     flag_descriptions::kBrowserContainerKeepsContentViewDescription,
-     flags_ui::kOsIos, FEATURE_VALUE_TYPE(kBrowserContainerKeepsContentView)},
     {"send-uma-cellular", flag_descriptions::kSendUmaOverAnyNetwork,
      flag_descriptions::kSendUmaOverAnyNetworkDescription, flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(kUmaCellular)},

ios/chrome/browser/flags/ios_chrome_flag_descriptions.cc

@@ -114,12 +114,6 @@ const char kBreakpadNoDelayInitialUploadDescription[] =
     "disabled, initial upload is delayed until deferred initialization. This "
     "does not affect recovery mode.";
 
-const char kBrowserContainerKeepsContentViewName[] =
-    "Browser Container retains the content view";
-const char kBrowserContainerKeepsContentViewDescription[] =
-    "When enable, the browser container keeps the content view in the view "
-    "hierarchy, to avoid WKWebView from being unloaded from the process.";
-
 const char kClearSyncedDataName[] = "Clear Synced Data on Sign Out";
 const char kClearSyncedDataDescription[] =
     "When enabled users signed in with a non-managed account will be "

ios/chrome/browser/flags/ios_chrome_flag_descriptions.h

@@ -88,11 +88,6 @@ extern const char kLogBreadcrumbsDescription[];
 extern const char kBreakpadNoDelayInitialUploadName[];
 extern const char kBreakpadNoDelayInitialUploadDescription[];
 
-// Title and description for the flag to make browser container keep the
-// content view hierarchy directly.
-extern const char kBrowserContainerKeepsContentViewName[];
-extern const char kBrowserContainerKeepsContentViewDescription[];
-
 // Title and description for the flag to control if Chrome should wipe synced
 // data from a local device on sign-out from a non-managed account.
 extern const char kClearSyncedDataName[];

ios/chrome/browser/ui/browser_view/browser_view_controller.mm

@@ -2370,19 +2370,7 @@ NSString* const kBrowserViewControllerSnackbarCategory =
       // TODO(crbug.com/873729): For a newly created WebState, the session will
       // not be restored until LoadIfNecessary call. Remove when fixed.
       webState->GetNavigationManager()->LoadIfNecessary();
-
-      // Always show the webState view under the NTP, to work around
-      // crbug.com/848789
-      if (base::FeatureList::IsEnabled(kBrowserContainerKeepsContentView)) {
-        if (self.browserContainerViewController.contentView !=
-            webState->GetView()) {
-          self.browserContainerViewController.contentView = webState->GetView();
-        }
-        self.browserContainerViewController.contentView.frame =
-            self.contentArea.bounds;
-      } else {
-        self.browserContainerViewController.contentView = nil;
-      }
+      self.browserContainerViewController.contentView = nil;
       self.browserContainerViewController.contentViewController =
           viewController;
     } else {

ios/chrome/browser/ui/ui_feature_flags.cc

@@ -4,9 +4,6 @@
 
 #include "ios/chrome/browser/ui/ui_feature_flags.h"
 
-const base::Feature kBrowserContainerKeepsContentView{
-    "BrowserContainerKeepsContentView", base::FEATURE_DISABLED_BY_DEFAULT};
-
 // TODO(crbug.com/945811): Using |-drawViewHierarchyInRect:afterScreenUpdates:|
 // has adverse flickering when taking a snapshot of the NTP while in the app
 // switcher.

ios/chrome/browser/ui/ui_feature_flags.h

@@ -7,9 +7,6 @@
 
 #include "base/feature_list.h"
 
-// Feature to retain the contentView in the browser container.
-extern const base::Feature kBrowserContainerKeepsContentView;
-
 // Feature to take snapshots using |-drawViewHierarchy:|.
 extern const base::Feature kSnapshotDrawView;