Add field to OmniboxIconView for tests

We want to check that the view is showing some icon in tests. This
exposes a readonly property for that case.

Bug: 963894
Change-Id: I2649ad4d4615cb41b4589cab6142978f747b97cd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1627375Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Commit-Queue: Robbie Gibson <rkgibson@google.com>
Cr-Commit-Position: refs/heads/master@{#663050}

ios/chrome/browser/ui/omnibox/popup/omnibox_icon_view.h

@@ -17,8 +17,10 @@
 
 // Used to fetch favicons.
 @property(nonatomic, weak) id<FaviconRetriever> faviconRetriever;
-
+// Used to fetch other images (rich entities, answers, etc.)
 @property(nonatomic, weak) id<ImageRetriever> imageRetriever;
+// Used for testing to check whether this view is displaying anything.
+@property(nonatomic, readonly) UIImage* mainImage;
 
 - (void)prepareForReuse;
 

ios/chrome/browser/ui/omnibox/popup/omnibox_icon_view.mm

@@ -145,4 +145,8 @@
   self.backgroundImageView.tintColor = omniboxIcon.backgroundImageTintColor;
 }
 
+- (UIImage*)mainImage {
+  return self.mainImageView.image;
+}
+
 @end