Don't compile code for desktop zoom or GuestViews on mobile platforms.

chrome/common/pref_names.h

 // Copyright (c) 2012 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_
 
 #include <stddef.h>
@@ skipping 362 matching lines @@
 #if defined(OS_MACOSX)
 extern const char kShowUpdatePromotionInfoBar[];
 #endif
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 extern const char kUseCustomChromeFrame[];
 #endif
 extern const char kBackShortcutBubbleShownCount[];
 #if BUILDFLAG(ENABLE_PLUGINS)
 extern const char kContentSettingsPluginWhitelist[];
 #endif
+#if !defined(OS_ANDROID)
 extern const char kPartitionDefaultZoomLevel[];
 extern const char kPartitionPerHostZoomLevels[];
 
-#if !defined(OS_ANDROID)
 extern const char kPinnedTabs[];
-#endif
+#endif  // !defined(OS_ANDROID)
 
 extern const char kDisable3DAPIs[];
 extern const char kEnableDeprecatedWebPlatformFeatures[];
 extern const char kEnableHyperlinkAuditing[];
 extern const char kEnableReferrers[];
 extern const char kEnableDoNotTrack[];
 
 extern const char kImportAutofillFormData[];
 extern const char kImportBookmarks[];
 extern const char kImportHistory[];
@@ skipping 515 matching lines @@
 extern const char kSettingsResetPromptLastTriggeredForStartupUrls[];
 extern const char kSettingsResetPromptLastTriggeredForHomepage[];
 
 #if defined(OS_ANDROID)
 extern const char kClipboardLastModifiedTime[];
 #endif
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_