Re-introduce the partial magnifier

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 174bb0804ec735cc75d6177b9ca590812ee7fefc..eaa2156bd40a7a610c0eba95cc480c857288b6d0 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -743,6 +743,10 @@ const char kSpokenFeedbackEnabled[] = "settings.accessibility";
 const char kHighContrastEnabled[] = "settings.a11y.high_contrast_enabled";
 // A boolean pref which determines whether screen magnifier is enabled.
 const char kScreenMagnifierEnabled[] = "settings.a11y.screen_magnifier";
+// A integer pref which determines what type of screen magnifier is enabled.
+// Note that: 'screen_magnifier_type' had been used as string pref. Hence,
+// we are using another name pref here.
+const char kScreenMagnifierType[] = "settings.a11y.screen_magnifier_type2";
 // A double pref which determines a zooming scale of the screen magnifier.
 const char kScreenMagnifierScale[] = "settings.a11y.screen_magnifier_scale";
 // A boolean pref which determines whether virtual keyboard is enabled.