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

chrome/common/pref_names.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Constants for the names of various preferences, for easier changing.
 
 #ifndef CHROME_COMMON_PREF_NAMES_H_
 #define CHROME_COMMON_PREF_NAMES_H_
 #pragma once
 
@@ skipping 396 matching lines @@
 extern const char kNTPWebStorePromoLogo[];
 extern const char kNTPWebStorePromoExpire[];
 extern const char kNTPWebStorePromoUserGroup[];
 
 extern const char kGpuBlacklist[];
 extern const char kGpuBlacklistUpdate[];
 
 extern const char kDevToolsDisabled[];
 extern const char kDevToolsOpenDocked[];
 extern const char kDevToolsSplitLocation[];
+extern const char kDevToolsWidgetHeight[];
 extern const char kSyncSessions[];
 
 extern const char kSyncLastSyncedTime[];
 extern const char kSyncHasSetupCompleted[];
 extern const char kKeepEverythingSynced[];
 extern const char kSyncBookmarks[];
 extern const char kSyncPasswords[];
 extern const char kSyncPreferences[];
 extern const char kSyncApps[];
 extern const char kSyncAutofill[];
@@ skipping 76 matching lines @@
 extern const char kCustomHandlersEnabled[];
 
 extern const char kUserCreatedLoginItem[];
 extern const char kBackgroundModeEnabled[];
 
 extern const char kDevicePolicyRefreshRate[];
 extern const char kUserPolicyRefreshRate[];
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_