Add update available icon in system tray

chrome/common/url_constants.h

Index: chrome/common/url_constants.h
diff --git a/chrome/common/url_constants.h b/chrome/common/url_constants.h
index 92531c6f24fe1b835c4a20ca70adb942fa0990d5..701a69d4b832aee18b8a0a8301b9bee70967c647 100644
--- a/chrome/common/url_constants.h
+++ b/chrome/common/url_constants.h
@@ -355,6 +355,7 @@ extern const char kInternetSubPage[];
 extern const char kNetworkDetailSubPage[];
 extern const char kPowerSubPage[];
 extern const char kStylusSubPage[];
+extern const char kHelpSubPage[];

[stevenjb, 2017/05/15 18:06:45]

I guess this is fine for now but FYI I just filed crbug.com/722450 to change
this to chrome://settings/about to better match the title and usage of the page.

[weidongg, 2017/05/15 20:06:57]

Ok, I see. Should I rename it to kAboutChromeOSPage?

[stevenjb, 2017/05/15 20:25:28]

We could, but I think that might be confusing, so maybe wait until we change the
url? Whichever seems less confusing to you.

[weidongg, 2017/05/16 19:46:08]

Ok, I see.

 #endif
 
 // Extensions sub pages.