[iOS] Enable support for finch experiment for Open from Clipboard.

ios/chrome/browser/experimental_flags.mm

Index: ios/chrome/browser/experimental_flags.mm
diff --git a/ios/chrome/browser/experimental_flags.mm b/ios/chrome/browser/experimental_flags.mm
index 5fd5926b221ac0801702b117c4cf16aaaa14cbbc..1697bb59ae1154b019834253ce6fec3fbef832ca 100644
--- a/ios/chrome/browser/experimental_flags.mm
+++ b/ios/chrome/browser/experimental_flags.mm
@@ -31,7 +31,10 @@ bool IsAlertOnBackgroundUploadEnabled() {
 
 bool IsOpenFromClipboardEnabled() {
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
-  return command_line->HasSwitch(switches::kEnableIOSOpenFromClipboard);
+  if (command_line->HasSwitch(switches::kEnableIOSOpenFromClipboard))
+    return true;
+  return base::FieldTrialList::FindFullName("IOSOpenFromClipboard") ==
+         "Enabled";
 }
 
 bool IsWKWebViewEnabled() {