Increase image cache to 100MB (#19220)

This should fix #18952 and #813

packages/flutter/lib/src/painting/image_cache.dart

@@ -5,18 +5,18 @@
 import 'image_stream.dart';
 
 const int _kDefaultSize = 1000;
-const int _kDefaultSizeBytes = 10485760; // 10 MiB
+const int _kDefaultSizeBytes = 100 << 20; // 100 MiB
 
 /// Class for the [imageCache] object.
 ///
-/// Implements a least-recently-used cache of up to 1000 images. The maximum
-/// size can be adjusted using [maximumSize]. Images that are actively in use
-/// (i.e. to which the application is holding references, either via
-/// [ImageStream] objects, [ImageStreamCompleter] objects, [ImageInfo] objects,
-/// or raw [dart:ui.Image] objects) may get evicted from the cache (and thus
-/// need to be refetched from the network if they are referenced in the
-/// [putIfAbsent] method), but the raw bits are kept in memory for as long as
-/// the application is using them.
+/// Implements a least-recently-used cache of up to 1000 images, and up to 100
+/// MB. The maximum size can be adjusted using [maximumSize] and
+/// [maximumSizeBytes]. Images that are actively in use (i.e. to which the
+/// application is holding references, either via [ImageStream] objects,
+/// [ImageStreamCompleter] objects, [ImageInfo] objects, or raw [dart:ui.Image]
+/// objects) may get evicted from the cache (and thus need to be refetched from
+/// the network if they are referenced in the [putIfAbsent] method), but the raw
+/// bits are kept in memory for as long as the application is using them.
 ///
 /// The [putIfAbsent] method is the main entry-point to the cache API. It
 /// returns the previously cached [ImageStreamCompleter] for the given key, if