adding DiscardableMemory preferences for deferred image decoding

webkit/glue/webpreferences.cc

Index: webkit/glue/webpreferences.cc
diff --git a/webkit/glue/webpreferences.cc b/webkit/glue/webpreferences.cc
index f5f6886a2a5ed69520e30123598b55ca770411c4..417de3f28d221f85c587370fdcfa3b346325964b 100644
--- a/webkit/glue/webpreferences.cc
+++ b/webkit/glue/webpreferences.cc
@@ -127,6 +127,8 @@ WebPreferences::WebPreferences()
       fixed_position_creates_stacking_context(false),
       sync_xhr_in_documents_enabled(true),
       deferred_image_decoding_enabled(false),
+      discardable_memory_limit_mb(32),
+      discardable_memory_entry_limit(128),
       should_respect_image_orientation(false),
       number_of_cpu_cores(1),
 #if defined(OS_MACOSX)
@@ -473,6 +475,8 @@ void WebPreferences::Apply(WebView* web_view) const {
       fixed_position_creates_stacking_context);
 
   settings->setDeferredImageDecodingEnabled(deferred_image_decoding_enabled);
+  settings->setDiscardableMemoryLimitMB(discardable_memory_limit_mb);
+  settings->setDiscardableMemoryEntryLimit(discardable_memory_entry_limit);
   settings->setShouldRespectImageOrientation(should_respect_image_orientation);
 
   settings->setUnsafePluginPastingEnabled(false);