[iOS][Diamond] Update omnibox look

This CL updates how the omnibox looks like in Diamond sheet.

https://screenshot.googleplex.com/8VrGiYJHxEN9T3x

Bug: 429955447
Change-Id: Iba91afc7396b397ff376953f6c9ce372ef00675d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6814253
Reviewed-by: Ewann Pellé <ewannpv@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Auto-Submit: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Ewann Pellé <ewannpv@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1496220}
diff --git a/ios/chrome/browser/shared/public/prototypes/diamond/new_tab_prototype_view_controller.mm b/ios/chrome/browser/shared/public/prototypes/diamond/new_tab_prototype_view_controller.mm
index 15a0495..a8957a5 100644
--- a/ios/chrome/browser/shared/public/prototypes/diamond/new_tab_prototype_view_controller.mm
+++ b/ios/chrome/browser/shared/public/prototypes/diamond/new_tab_prototype_view_controller.mm
@@ -144,6 +144,11 @@
   _omniboxContainer = [[UIView alloc] init];
   _omniboxContainer.translatesAutoresizingMaskIntoConstraints = NO;
   _omniboxContainer.backgroundColor = [UIColor colorNamed:kSolidWhiteColor];
+  _omniboxContainer.layer.shadowColor =
+      [UIColor colorNamed:kSolidBlackColor].CGColor;
+  _omniboxContainer.layer.shadowOffset = CGSizeMake(0, 5);
+  _omniboxContainer.layer.shadowOpacity = 0.2;
+  _omniboxContainer.layer.shadowRadius = 5;
   _omniboxContainer.layer.cornerRadius = kOmniboxContainerHeight / 2.0;
   [self.view addSubview:_omniboxContainer];