Add settings UI for managing defaults

Add new "Manage preferred service..." button to web intents settings UI.
Update message naming to use common naming pattern.

BUG=137907

[Steve McKay, 2012-08-08 21:41:18]

This CL depends on 10824212 which is currently being committed. So there's one
line of commented out code for now. But there's a lot of code here that needs
review, so I thought I'd get things started.

Dan, looks like you're an OWNER, so added you for your expertise. This settings
code has a high magic factor :) A knowledgeable experts eye would be
appreciated.

[Steve McKay, 2012-08-08 22:46:38]

Assigning to Chris since Dan isn't available.

[csilv, 2012-08-09 18:18:04]

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/resources/op...
File chrome/browser/resources/options2/content_settings.html (right):

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/resources/op...
chrome/browser/resources/options2/content_settings.html:254: <h3
i18n-content="web_intents_tab_label"
Although this rule isn't followed consistently, we prefer camelCase for
i18n-content tags
(http://dev.chromium.org/developers/web-development-style-guide).  Let's follow
the rule, someday one of us will do a global fix for the others.

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/resources/op...
File chrome/browser/resources/options2/options_page.js (right):

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/resources/op...
chrome/browser/resources/options2/options_page.js:82: 
intentional newline? (revert?)

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/resources/op...
File chrome/browser/resources/options2/web_intents_defaults.js (right):

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/resources/op...
chrome/browser/resources/options2/web_intents_defaults.js:13: * @constructor
nit: @extends OptionsPage

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/resources/op...
File chrome/browser/resources/options2/web_intents_defaults_list.js (right):

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/resources/op...
chrome/browser/resources/options2/web_intents_defaults_list.js:40: // add
favicon for the service URL
this this a TODO...?

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/ui/webui/opt...
File chrome/browser/ui/webui/options2/content_settings_handler.cc (right):

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/ui/webui/opt...
chrome/browser/ui/webui/options2/content_settings_handler.cc:419: {
"web_intents_enabled", IDS_WEB_INTENTS_ENABLED },
per previous comment, camelCase

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/ui/webui/opt...
File chrome/browser/ui/webui/options2/web_intents_defaults_handler.cc (right):

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/ui/webui/opt...
chrome/browser/ui/webui/options2/web_intents_defaults_handler.cc:78:
IDS_WEB_INTENTS_DEFAULTS_TITLE_COLUMN },
per previous comment, camelCase for i18n keys.

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/ui/webui/opt...
chrome/browser/ui/webui/options2/web_intents_defaults_handler.cc:87: // TODO:
plug into notifications to monitor registry changes.
nit: TODO(smckay)

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/ui/webui/opt...
chrome/browser/ui/webui/options2/web_intents_defaults_handler.cc:109: 
nit: bikesheding, i'm not crazy about these newlines at the top of a method some
of these methods, but i'm not asking for a change... just mentioning it.  :-)

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/ui/webui/opt...
chrome/browser/ui/webui/options2/web_intents_defaults_handler.cc:125: //
GetRegistry()->UnregisterServiceDefaults(service_url);
why is this commented out..?

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/ui/webui/opt...
File chrome/browser/ui/webui/options2/web_intents_defaults_handler.h (right):

http://codereview.chromium.org/10808092/diff/5003/chrome/browser/ui/webui/opt...
chrome/browser/ui/webui/options2/web_intents_defaults_handler.h:6: #define
CHROME_BROWSER_UI_WEBUI_OPTIONS2_MEDIA_GALLERY_HANDLER_H_
CHROME_BROWSER_UI_WEBUI_OPTIONS2_WEB_INTENTS_DEFAULTS_HANDLER_H_

[Steve McKay, 2012-08-30 16:19:42]

This appears to be officially dead now. Closing.