[MD settings] adding get/set for default page zoom to settings private

These changes will be used by the Appearance
Material Design settings.

BUG=531786

Review URL: https://codereview.chromium.org/1430893003

Cr-Commit-Position: refs/heads/master@{#358620}
diff --git a/extensions/browser/extension_function_histogram_value.h b/extensions/browser/extension_function_histogram_value.h
index e9c34fc..67b8a725 100644
--- a/extensions/browser/extension_function_histogram_value.h
+++ b/extensions/browser/extension_function_histogram_value.h
@@ -1152,6 +1152,8 @@
   TABCAPTURE_CAPTUREOFFSCREENTAB,
   LANGUAGESETTINGSPRIVATE_ADDSPELLCHECKWORD,
   LANGUAGESETTINGSPRIVATE_REMOVESPELLCHECKWORD,
+  SETTINGSPRIVATE_GETDEFAULTZOOMPERCENTFUNCTION,
+  SETTINGSPRIVATE_SETDEFAULTZOOMPERCENTFUNCTION,
   // Last entry: Add new entries above, then run:
   // python tools/metrics/histograms/update_extension_histograms.py
   ENUM_BOUNDARY