Show all mailto: handlers, but dim unavailable ones.

ios/chrome/browser/ui/settings/compose_email_handler_collection_view_controller.mm

Index: ios/chrome/browser/ui/settings/compose_email_handler_collection_view_controller.mm
diff --git a/ios/chrome/browser/ui/settings/compose_email_handler_collection_view_controller.mm b/ios/chrome/browser/ui/settings/compose_email_handler_collection_view_controller.mm
index 71010f36ccdaf758b63926738c54d99894ddb2e5..a7652498cf6d6cb2337c754c0e27ae3b33c4c424 100644
--- a/ios/chrome/browser/ui/settings/compose_email_handler_collection_view_controller.mm
+++ b/ios/chrome/browser/ui/settings/compose_email_handler_collection_view_controller.mm
@@ -6,6 +6,7 @@
 
 #include "base/mac/foundation_util.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_text_item.h"
+#import "ios/chrome/browser/ui/colors/MDCPalette+CrAdditions.h"

[rohitrao (ping after 24h), 2017/05/22 12:50:37]

If all you need is greyColor, you should be able to depend directly on the MDC
Palette component.  (The +CrAdditions are there for red/green/blue/yellow
specifically.)

Changes here and in the BUILD.gn file.

[pkl (ping after 24h if needed), 2017/05/22 20:27:09]

Thanks! Makes sense.

 #import "ios/chrome/browser/web/mailto_handler.h"
 #import "ios/chrome/browser/web/mailto_url_rewriter.h"
 #include "ios/chrome/grit/ios_strings.h"
@@ -56,13 +57,18 @@ typedef NS_ENUM(NSInteger, ItemType) {
   // choice available to the user. If this UI is being presented when there is
   // only one choice, it is considered a software error.
   NSArray<MailtoHandler*>* handlers = [_rewriter defaultHandlers];
-  DCHECK([handlers count] > 1);
   NSString* currentHandlerID = [_rewriter defaultHandlerID];
   for (MailtoHandler* handler in handlers) {
     CollectionViewTextItem* item =
         [[CollectionViewTextItem alloc] initWithType:ItemTypeMailtoHandlers];
     [item setText:[handler appName]];
-    [item setAccessibilityTraits:UIAccessibilityTraitButton];
+    if ([handler isAvailable]) {
+      [item setTextColor:[[MDCPalette greyPalette] tint900]];
+      [item setAccessibilityTraits:UIAccessibilityTraitButton];
+    } else {
+      [item setTextColor:[[MDCPalette greyPalette] tint500]];
+      [item setAccessibilityTraits:UIAccessibilityTraitNotEnabled];
+    }
     if ([currentHandlerID isEqualToString:[handler appStoreID]])
       [item setAccessoryType:MDCCollectionViewCellAccessoryCheckmark];
     [model addItem:item
@@ -87,6 +93,13 @@ typedef NS_ENUM(NSInteger, ItemType) {
   if (selectedItem.accessoryType == MDCCollectionViewCellAccessoryCheckmark)
     return;
 
+  // Do nothing if the handler for the tapped row is not available.

[rohitrao (ping after 24h), 2017/05/22 12:50:37]

Consider handling this in shouldSelectItemAtIndexPath instead.  If you put the
logic is there, it may also disable the "ink" effect for free.  (We probably
don't want the ink ripple to fire for dimmed-out cells.)

[pkl (ping after 24h if needed), 2017/05/22 20:27:09]

Added shouldSelectItemAtIndexPath:, however it does not stop the ink ripple.
To stop ink ripple, I added shouldHighlightItemAtIndexPath: as well.

+  NSUInteger handlerIndex = [model indexInItemTypeForIndexPath:indexPath];
+  MailtoHandler* handler =
+      [[_rewriter defaultHandlers] objectAtIndex:handlerIndex];
+  if (![handler isAvailable])
+    return;
+
   // Iterate through the rows and remove the checkmark from any that has it.
   NSMutableArray* modifiedItems = [NSMutableArray array];
   for (id item in
@@ -106,9 +119,6 @@ typedef NS_ENUM(NSInteger, ItemType) {
     }
   }
 
-  NSUInteger handlerIndex = [model indexInItemTypeForIndexPath:indexPath];
-  MailtoHandler* handler =
-      [[_rewriter defaultHandlers] objectAtIndex:handlerIndex];
   [_rewriter setDefaultHandlerID:[handler appStoreID]];
 
   [self reconfigureCellsForItems:modifiedItems];