DevTools window doesn't restore its minimal size if it's shrinked to zero.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 80a07af7e507bf040997b303cc40b6c412810e75..876ca0c47dbce4e41d6e49088849312c4e5043bb 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1174,6 +1174,9 @@ const char kDevToolsOpenDocked[] = "devtools.open_docked";
 // Integer location of the split bar in the browser view.
 const char kDevToolsSplitLocation[] = "devtools.split_location";
 
+// Integer height of the devtools widget in the browser view.
+const char kDevToolsWidgetHeight[] = "devtools.widget_height";
+
 // 64-bit integer serialization of the base::Time when the last sync occurred.
 const char kSyncLastSyncedTime[] = "sync.last_synced_time";