Allow only compact widget size when all sites shown

When all the sites fit on a single row (as is the case for most
devices now that only 4 sites are shown), hide the "Show more"
option and allow only compact mode.

Bug: 860799
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: If2efa48bcd1cbe23c49b34be4ec084f95a703d08
Reviewed-on: https://chromium-review.googlesource.com/1143464Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Elodie Banel <lod@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576505}

ios/chrome/content_widget_extension/content_widget_view.h

@@ -48,6 +48,9 @@
 // positions starting at 0.
 - (void)updateSites:(NSDictionary<NSURL*, NTPTile*>*)sites;
 
+// Returns whether all the sites can be displayed on a single row.
+- (BOOL)sitesFitSingleRow;
+
 @end
 
 #endif  // IOS_CHROME_CONTENT_WIDGET_EXTENSION_CONTENT_WIDGET_VIEW_H_

ios/chrome/content_widget_extension/content_widget_view.mm

@@ -252,6 +252,10 @@ const int kRows = 2;
   return self.shouldShowSecondRow ? kTileHeight + kTileSpacing : 0;
 }
 
+- (BOOL)sitesFitSingleRow {
+  return self.iconsPerRow >= self.siteCount;
+}
+
 #pragma mark - ContentWidgetView
 
 - (void)showMode:(BOOL)compact {

ios/chrome/content_widget_extension/content_widget_view_controller.mm

@@ -80,7 +80,7 @@ NSString* const kXCallbackURLHost = @"x-callback-url";
   [self.view addSubview:self.widgetView];
 
   self.extensionContext.widgetLargestAvailableDisplayMode =
-      NCWidgetDisplayModeExpanded;
+      NCWidgetDisplayModeCompact;
 
   self.widgetView.translatesAutoresizingMaskIntoConstraints = NO;
   AddSameConstraints(self.widgetView, self.view);
@@ -149,6 +149,9 @@ NSString* const kXCallbackURLHost = @"x-callback-url";
   }
   self.sites = newSites;
   [self.widgetView updateSites:self.sites];
+  self.extensionContext.widgetLargestAvailableDisplayMode =
+      [self.widgetView sitesFitSingleRow] ? NCWidgetDisplayModeCompact
+                                          : NCWidgetDisplayModeExpanded;
   return YES;
 }