Skip per-script font preferences registration and filling on Android.

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 db0b657a2219b0b22cd9a71937ca31a6bf632754..226b0c31d59a7792b77809b27b6d50c4239143dc 100644
--- a/chrome/browser/ui/prefs/prefs_tab_helper.cc
+++ b/chrome/browser/ui/prefs/prefs_tab_helper.cc
@@ -138,12 +138,15 @@ const char* kPrefsToObserve[] = {
 
 const int kPrefsToObserveLength = arraysize(kPrefsToObserve);
 
+#if !defined(OS_ANDROID)
 // Registers a preference under the path |pref_name| for each script used for
 // per-script font prefs.
 // For example, for WEBKIT_WEBPREFS_FONTS_SERIF ("fonts.serif"):
 // "fonts.serif.Arab", "fonts.serif.Hang", etc. are registered.
 // |fonts_with_defaults| contains all |pref_names| already registered since they
 // have a specified default value.
+// On Android there are no default values for these properties and there is no
+// way to set them, so we can avoid registering them altogether.

[falken, 2013/10/17 12:23:29]

Maybe mention that the way to set them on other platforms is through the
extension API, something like:
"On Android, the prefs have no default values and as there are no extensions the
Font Settings API cannot be used to set them, so we can avoid registering them
altogether."

[ppi, 2013/10/17 16:49:04]

Done.

 void RegisterFontFamilyPrefs(user_prefs::PrefRegistrySyncable* registry,
                              const std::set<std::string>& fonts_with_defaults) {
 
@@ -177,7 +180,6 @@ ALL_FONT_SCRIPTS(WEBKIT_WEBPREFS_FONTS_STANDARD)
   }
 }
 
-#if !defined(OS_ANDROID)
 // Registers |obs| to observe per-script font prefs under the path |map_name|.
 // On android, there's no exposed way to change these prefs, so we can save
 // ~715KB of heap and some startup cycles by avoiding observing these prefs
@@ -612,8 +614,10 @@ void PrefsTabHelper::RegisterProfilePrefs(
     }
   }
 
-  // Register font prefs that don't have defaults.
+  // Register per-script font prefs that don't have defaults.
+#if !defined(OS_ANDROID)
   RegisterFontFamilyPrefs(registry, fonts_with_defaults);
+#endif
 
   registry->RegisterLocalizedIntegerPref(
       prefs::kWebKitDefaultFontSize,