Clipboard Android - Store and Read Last Modified Time from Prefs

ui/base/clipboard/clipboard_android.h

Index: ui/base/clipboard/clipboard_android.h
diff --git a/ui/base/clipboard/clipboard_android.h b/ui/base/clipboard/clipboard_android.h
index 8589e9c75587b2936c5ae3c27c9b2dd40b0e7cf7..4a222e4bd18ef2fd743409b7ad5fe71d7fd3423f 100644
--- a/ui/base/clipboard/clipboard_android.h
+++ b/ui/base/clipboard/clipboard_android.h
@@ -15,10 +15,22 @@
 #include "base/macros.h"
 #include "base/time/time.h"
 
+class PrefService;
+class PrefRegistrySimple;
+
 namespace ui {
 
 class ClipboardAndroid : public Clipboard {
  public:
+  // Exported only so
+  // chrome/browser/android/preferences/browser_prefs_android.cc
+  // can call it.
+  static UI_BASE_EXPORT void RegisterPrefs(PrefRegistrySimple* registry);

[Ted C, 2017/04/24 20:45:48]

I would have expected static to come after the UI_BASE_EXPORT, but it seems
pretty split in ui/ (more heavily biased to coming first in content/ though).

[Mark P, 2017/04/24 22:19:56]

Acknowledged.  Swapped the order simply because the new order makes it align
better with the function below.

+
+  // Called during startup when local state is available to store a pointer to
+  // local_state in order to read and update prefs.
+  UI_BASE_EXPORT void SetLocalState(PrefService* local_state);

[Ted C, 2017/04/24 20:45:48]

local state is not something that is super easy to grok in my opinion (although
it might have more awareness with the rest of chromium in which case ignore
this).  I think SetPrefService is clearer to me.  Does it really matter that it
came from g_browser_process->local_state()?

[Mark P, 2017/04/24 22:19:56]

I understand SetPrefService seems clearer and probably is clearer for most
folks, yet I think most folks would take it wrong.  When talking about this
changelist with other people (in person and via e-mail), I learned that
virtually everything assumes "pref" implies "per-profile".  I wanted to make the
function name make clear that this was something different.

I don't feel strongly about this choice if people object.  That's just my
reasoning.

[dcheng, 2017/04/25 13:17:12]

PrefService does seem profile-specific to me, while local state is just a
completely unknown beast. Maybe we could improve our docs in this area somewhat
(or maybe they already exist and I don't know where they are).

All this is to say I slightly prefer local state (once I understood what it
meant)

[Mark P, 2017/04/25 18:51:21]

Left function name as-is as previously discussed.  Expanded comment to clarify
what "local state" is.

+
   // Called by Java when the Java Clipboard is notified that the clipboard has
   // changed.
   void OnPrimaryClipChanged(JNIEnv* env,