Revamp the MigrateBrowserPrefs and MigrateUserPrefs code.

chrome/common/pref_names.h

Index: chrome/common/pref_names.h
diff --git a/chrome/common/pref_names.h b/chrome/common/pref_names.h
index c4c6bc3f91dfa3b444a475ffbcbdbea68f0078cc..5152f0ce3baa8d1e0cb39f5285ec140b4a43f3e1 100644
--- a/chrome/common/pref_names.h
+++ b/chrome/common/pref_names.h
@@ -165,7 +165,7 @@ extern const char kDisabledSchemes[];
 extern const char kLastPolicyCheckTime[];
 #endif
 extern const char kInstantUIZeroSuggestUrlPrefix[];
-extern const char kMultipleProfilePrefMigration[];
+extern const char kMultipleProfilePrefMigration[]; // OBSOLETE

[rkaplow, 2015/02/20 21:58:08]

some are marked OBSOLETE. Should I be removing this at this point or just mark
as OBSOLETE?

[gab, 2015/02/23 16:09:37]

The other ones FWICT are declared globally but only used locally for cleanup.

I'd prefer that the ones only needed in browser_prefsl.cc be removed from this
global declaration file and moved to a local file scope declaration in
browser_prefs.cc so that despite still needing them for a while, we keep the
cleanup code as local as possible.

(consider doing this for the 3 existing OBSOLETE prefs as part of this CL as
well)

[rkaplow, 2015/02/23 23:27:52]

already having a bit of trouble keeping track of everything so will not do that
as part of this CL. Added TODO

[gab, 2015/02/24 20:55:19]

Ok NP, though I think kCookieBehavior is the only remaining such OBSOLETE pref
after you removed 2/3 of them in this CL (and it's not referred to by any code,
so it looks like a 2-line strip with no side-effects which may just be easier to
do in this CL)... I rarely advocate for more in the same CL (in fact this CL
could probably be split up but it's not that hard to follow as-is so I didn't
suggest doing so), but in this case feels simple enough to include in this CL.

[rkaplow, 2015/02/24 22:41:11]

You're correct. Done

 extern const char kNetworkPredictionEnabled[];
 extern const char kNetworkPredictionOptions[];
 extern const char kDefaultAppsInstallState[];
@@ -491,7 +491,6 @@ extern const char kUninstallLastObservedRunTimeSec[];
 
 extern const char kBrowserSuppressDefaultBrowserPrompt[];
 
-extern const char kBrowserWindowPlacement[];
 extern const char kBrowserWindowPlacementPopup[];
 extern const char kTaskManagerWindowPlacement[];
 extern const char kAppWindowPlacement[];