Change favicon size for search engine settings.

Change the desired favicon size in points from 24 to 32 for search
settings, since favicons for prepopulated search engines will be fetched
from google favicon server which only supports 16,32,64,96,180. Favicon
size will be multiplied by screen scale(1, 2, 3), so changing the size
to 32 will meet the size expectation(32, 64, 96) of favicon server.
Otherwise the server will return an icon with default size(16x16), which
looks blur.

Bug: 953246
Change-Id: Ief3ac90941b428987b55dfb298291036484147d8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1581202Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Yi Su <mrsuyi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#653536}

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

@@ -42,6 +42,8 @@ typedef NS_ENUM(NSInteger, ItemType) {
 
 const CGFloat kTableViewSeparatorLeadingInset = 56;
 const CGFloat kTableViewSeparatorTrailingInset = 16;
+const int kFaviconDesiredSizeInPoint = 32;
+const int kFaviconMinSizeInPoint = 16;
 constexpr base::TimeDelta kMaxVisitAge = base::TimeDelta::FromDays(2);
 const size_t kMaxcustomSearchEngines = 3;
 const char kUmaSelectDefaultSearchEngine[] =
@@ -232,7 +234,7 @@ const char kUmaSelectDefaultSearchEngine[] =
     FaviconAttributes* cachedAttributes = nil;
     if (item.type == ItemTypePrepopulatedEngine) {
       cachedAttributes = _faviconLoader->FaviconForPageUrl(
-          engineItem.URL, kFaviconPreferredSize, kFaviconMinSize,
+          engineItem.URL, kFaviconDesiredSizeInPoint, kFaviconMinSizeInPoint,
           /*fallback_to_google_server=*/YES, ^(FaviconAttributes* attributes) {
             // Only set favicon if the cell hasn't been reused.
             if (urlCell.cellUniqueIdentifier == engineItem.uniqueIdentifier) {
@@ -242,7 +244,7 @@ const char kUmaSelectDefaultSearchEngine[] =
           });
     } else {
       cachedAttributes = _faviconLoader->FaviconForIconUrl(
-          engineItem.URL, kFaviconPreferredSize, kFaviconMinSize,
+          engineItem.URL, kFaviconDesiredSizeInPoint, kFaviconMinSizeInPoint,
           ^(FaviconAttributes* attributes) {
             // Only set favicon if the cell hasn't been reused.
             if (urlCell.cellUniqueIdentifier == engineItem.uniqueIdentifier) {