Rename remaining instances of high efficiency to memory saver

This is one of a set of CLs to rename the "high efficiency" feature to
"memory saver" to match the branding we launched with and resolve
confusion when searching for code. All CLs are tagged with
#rename-high-efficiency. I plan to wait for most of them to be
approved before starting to submit these changes to ensure the code
remains in a consistent state. After submitting these CLs I'll make
another pass to capture any remaining references that can be changed.

#rename-high-efficiency

Bug: 1493843
Change-Id: I7f36f6eb836032cd3718fc672731f2b1199e2a76
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5117972
Commit-Queue: Alison Gale <[email protected]>
Code-Coverage: [email protected] <[email protected]>
Reviewed-by: Joe Mason <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1237539}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 6774e3f2..207f74c 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -2010,8 +2010,8 @@
   RegisterProfilePrefsForMigration(registry);
 
 #if !BUILDFLAG(IS_ANDROID)
-  registry->RegisterIntegerPref(prefs::kHighEfficiencyChipExpandedCount, 0);
-  registry->RegisterTimePref(prefs::kLastHighEfficiencyChipExpandedTimestamp,
+  registry->RegisterIntegerPref(prefs::kMemorySaverChipExpandedCount, 0);
+  registry->RegisterTimePref(prefs::kLastMemorySaverChipExpandedTimestamp,
                              base::Time());
 #endif