[iOS] Set FirstResponderSendAction as default

Remove experiment flag, and set enabled behavior as default.

Keep old behavior when asking the NTP and WebView to become first
responder. This is done checking if the first responder is a view, and
asking if not. Because in the previous logic for GetFirstResponder() the
search was made in the view hierarchy, ignoring view controllers.

The experiment enabled without the check added in this CL could explain
issues like crbug.com/1150498.

Bug: 816427, 1150498
Change-Id: Ib9ac17b59da8635d00beff071aee4bd6afeedb78
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2495976Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Javier Flores <javierrobles@chromium.org>
Auto-Submit: Javier Flores <javierrobles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#830632}

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

@@ -3772,9 +3772,12 @@ NSString* const kBrowserViewControllerSnackbarCategory =
     [SizeClassRecorder pageLoadedWithHorizontalSizeClass:sizeClass];
   }
 
-  // If there is no first responder, try to make the webview or the NTP first
-  // responder to have it answer keyboard commands (e.g. space bar to scroll).
-  if (!GetFirstResponder() && self.currentWebState) {
+  // If there is no first responder, or it is not a view, try to make the
+  // webview or the NTP first responder to have it answer keyboard commands
+  // (e.g. space bar to scroll).
+  BOOL isFirstResponderView =
+      [GetFirstResponder() isKindOfClass:[UIView class]];
+  if (!isFirstResponderView && self.currentWebState) {
     NewTabPageTabHelper* NTPHelper =
         NewTabPageTabHelper::FromWebState(webState);
     if (NTPHelper && NTPHelper->IsActive()) {

ios/chrome/browser/ui/ui_feature_flags.cc

@@ -31,9 +31,6 @@ const base::Feature kForceUnstackedTabstrip{"ForceUnstackedTabstrip",
 const base::Feature kTestFeature{"TestFeature",
                                  base::FEATURE_DISABLED_BY_DEFAULT};
 
-const base::Feature kFirstResponderSendAction{
-    "FirstResponderSendAction", base::FEATURE_DISABLED_BY_DEFAULT};
-
 const base::Feature kEnableNativeContextMenus{
     "EnableNativeContextMenus", base::FEATURE_DISABLED_BY_DEFAULT};
 

ios/chrome/browser/ui/ui_feature_flags.h

@@ -34,9 +34,6 @@ extern const base::Feature kForceUnstackedTabstrip;
 // features in tests works.
 extern const base::Feature kTestFeature;
 
-// Verify if the crash in https://crbug.com/816427 is fixed on iOS 12.
-extern const base::Feature kFirstResponderSendAction;
-
 // Feature flag that enables the native UI Context Menus (not for Web content).
 extern const base::Feature kEnableNativeContextMenus;
 

ios/chrome/browser/ui/util/uikit_ui_util.h

@@ -181,7 +181,7 @@ bool IsSplitToolbarMode(id<UITraitEnvironment> environment);
 // bottom toolbar or if it is displayed as only one toolbar.
 bool IsSplitToolbarMode(UITraitCollection* traitCollection);
 
-// Returns the current first responder for keyWindow.
+// Returns the current first responder.
 UIResponder* GetFirstResponder();
 
 // Trigger a haptic vibration for various types of actions. This is a no-op for

ios/chrome/browser/ui/util/uikit_ui_util.mm

@@ -315,19 +315,15 @@ UIView* GetFirstResponderSubview(UIView* view) {
 
 UIResponder* GetFirstResponder() {
   DCHECK_CURRENTLY_ON(web::WebThread::UI);
-  if (base::FeatureList::IsEnabled(kFirstResponderSendAction)) {
-    DCHECK_CURRENTLY_ON(web::WebThread::UI);
-    DCHECK(!g_first_responder);
-    [[UIApplication sharedApplication]
-        sendAction:@selector(cr_markSelfCurrentFirstResponder)
-                to:nil
-              from:nil
-          forEvent:nil];
-    UIResponder* firstResponder = g_first_responder;
-    g_first_responder = nil;
-    return firstResponder;
-  }
-  return GetFirstResponderSubview([UIApplication sharedApplication].keyWindow);
+  DCHECK(!g_first_responder);
+  [[UIApplication sharedApplication]
+      sendAction:@selector(cr_markSelfCurrentFirstResponder)
+              to:nil
+            from:nil
+        forEvent:nil];
+  UIResponder* firstResponder = g_first_responder;
+  g_first_responder = nil;
+  return firstResponder;
 }
 
 // Trigger a haptic vibration for the user selecting an action. This is a no-op