[ios] Add missing dependency on CoreImage

As the code uses types from CoreImage (CIFilter, CIImage, ...), it
needs to declare a dependency. Currently the build works because
this dependency comes from Firebase SDK, but it will become required
once Firebase is provided through the internal framework.

Bug: 1049042
Change-Id: Ib5cda246ab82b7492c6462564006230862dcd019
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2153068
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759737}

ios/chrome/browser/ui/qr_generator/BUILD.gn

@@ -18,7 +18,10 @@ source_set("ui") {
     "//ui/base",
     "//url:url",
   ]
-  libs = [ "UIKit.framework" ]
+  frameworks = [
+    "UIKit.framework",
+    "CoreImage.framework",
+  ]
 }
 
 source_set("qr_generator") {

ios/chrome/browser/ui/qr_generator/qr_generator_util.mm

@@ -4,6 +4,8 @@
 
 #import "ios/chrome/browser/ui/qr_generator/qr_generator_util.h"
 
+#import <CoreImage/CoreImage.h>
+
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif