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

chrome/browser/ui/prefs/prefs_tab_helper.cc

Index: chrome/browser/ui/prefs/prefs_tab_helper.cc
diff --git a/chrome/browser/ui/prefs/prefs_tab_helper.cc b/chrome/browser/ui/prefs/prefs_tab_helper.cc
index 62396a3d93be1a95c3b1f7acdfa6b34814a9e139..d0830f5531be38348838c5c8c1a7e3972f654329 100644
--- a/chrome/browser/ui/prefs/prefs_tab_helper.cc
+++ b/chrome/browser/ui/prefs/prefs_tab_helper.cc
@@ -24,7 +24,6 @@
 #include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/renderer_preferences_util.h"
-#include "chrome/browser/ui/zoom/chrome_zoom_level_prefs.h"
 #include "chrome/common/pref_font_webkit_names.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/pref_names_util.h"
@@ -60,6 +59,10 @@
 #include "base/win/windows_version.h"
 #endif
 
+#if !defined(OS_ANDROID)

[Bernhard Bauer, 2017/05/15 09:33:28]

Can you move this up before OS_POSIX etc. so the blocks are approximately
alphabetical?

[Kevin McNee, 2017/05/15 20:02:10]

Done.

+#include "chrome/browser/ui/zoom/chrome_zoom_level_prefs.h"
+#endif
+
 using content::WebContents;
 using content::WebPreferences;
 
@@ -473,19 +476,23 @@ PrefsTabHelper::PrefsTabHelper(WebContents* contents)
       weak_ptr_factory_(this) {
   PrefService* prefs = profile_->GetPrefs();
   if (prefs) {
+#if !defined(OS_ANDROID)
     // If the tab is in an incognito profile, we track changes in the default
     // zoom level of the parent profile instead.
     Profile* profile_to_track = profile_->GetOriginalProfile();
     ChromeZoomLevelPrefs* zoom_level_prefs =
         profile_to_track->GetZoomLevelPrefs();
+#endif  // !defined(OS_ANDROID)
 
     base::Closure renderer_callback = base::Bind(

[msw, 2017/05/12 18:06:32]

It seems like you can include this in a !defined(OS_ANDROID) block, and merge
the two blocks above and below.

[Kevin McNee, 2017/05/15 20:02:10]

Done.

         &PrefsTabHelper::UpdateRendererPreferences, base::Unretained(this));
+#if !defined(OS_ANDROID)
     // Tests should not need to create a ZoomLevelPrefs.
     if (zoom_level_prefs) {
       default_zoom_level_subscription_ =
           zoom_level_prefs->RegisterDefaultZoomLevelCallback(renderer_callback);
     }
+#endif  // !defined(OS_ANDROID)
 
     PrefWatcher::Get(profile_)->RegisterHelper(this);
   }