More pre-MD odds and ends.

extensions/common/constants.h

Index: extensions/common/constants.h
diff --git a/extensions/common/constants.h b/extensions/common/constants.h
index 4e1ef6a974a8733d9034ea4e4bb4f5c30704759d..b6b1bca29a90295e28e38fb4d68f1cceff68543f 100644
--- a/extensions/common/constants.h
+++ b/extensions/common/constants.h
@@ -188,8 +188,6 @@ const int kUnknownWindowId = -1;
 // Matches chrome.windows.WINDOW_ID_CURRENT.
 const int kCurrentWindowId = -2;
 
-// NOTE: If you change this list, you should also change kExtensionIconSizes
-// in cc file.
 enum ExtensionIcons {
   EXTENSION_ICON_GIGANTOR = 512,
   EXTENSION_ICON_EXTRA_LARGE = 256,
@@ -197,7 +195,6 @@ enum ExtensionIcons {
   EXTENSION_ICON_MEDIUM = 48,
   EXTENSION_ICON_SMALL = 32,
   EXTENSION_ICON_SMALLISH = 24,
-  EXTENSION_ICON_ACTION = 19,

[Devlin, 2016/11/02 00:52:12]

I think I'd prefer we keep this, and just update it to also be 16. 
Conceptually, it's use remains the same - it's the size of the extension action
in the toolbar.

[Evan Stade, 2016/11/02 13:14:05]

I think that creates a mismatch between this value, which describes a semantic
usage, and the rest of the values in this enum, which are ambivalent about how
they're applied. The logical connection between 16 and extension actions is
provided by ExtensionAction::ActionIconSize().

Nevertheless, done.

[Devlin, 2016/11/02 23:16:52]

You've convinced me.  For some reason in the original patch, I swear I saw more
usages of ICON_BITTY than of using ExtensionAction::ActionIconSize().

   EXTENSION_ICON_BITTY = 16,
   EXTENSION_ICON_INVALID = 0,
 };