Add cr-checkbox to Chrome

ui/webui/resources/cr_elements/cr_checkbox/cr_checkbox.html

Index: ui/webui/resources/cr_elements/cr_checkbox/cr_checkbox.html
diff --git a/ui/webui/resources/cr_elements/cr_checkbox/cr_checkbox.html b/ui/webui/resources/cr_elements/cr_checkbox/cr_checkbox.html
new file mode 100644
index 0000000000000000000000000000000000000000..d4a641fffa7614a7886abfb365f27df49d2078a5
--- /dev/null
+++ b/ui/webui/resources/cr_elements/cr_checkbox/cr_checkbox.html
@@ -0,0 +1,15 @@
+<link rel="import"
+    href="chrome://resources/polymer/paper-checkbox/paper-checkbox.html">
+<link rel="import"
+    href="chrome://resources/cr_elements/cr_events/cr_events.html">

[Dan Beam, 2015/02/13 21:56:49]

that's weird.  why are we using _ when polymer uses -?

[Dan Beam, 2015/02/13 21:56:49]

chrome cr cr cr :(

[michaelpg, 2015/02/13 23:27:57]

cf. paper-checkbox/paper-checkbox.html

"cr_events/cr_events.*" is pretty much *the* convention in Polymer-land (except
the underscore).

"chrome://elements/" doesn't imply "chrome elements" any more than
"chrome://polymer/" implies "chrome polymer elements".

[michaelpg, 2015/02/13 23:27:57]

yeah. We decided to be consistent with the rest of Chromium and use underscores
everywhere. Having hyphens in the file names but underscores in the directory
names is also weird.

[Dan Beam, 2015/02/19 22:47:56]

that's repetitive. that's repetitive.

it wastes space and my time. it wastes space and my time.

don't you wish you got those 10s back? don't you wish you got those 10s back?
I'm confused: are we in chrome or polymer land?  you just said "we willingly
disobey polymer when it comes to - vs _" but we don't when it comes to saving us
tons of wrapped lines?
I don't get what you mean here.

English is made up of words strung together. Code is written in/like English.
That's why conditional operators are if/else/then, for example, so it reads like
logical English.

When you glean the English of "chrome://elements", YES is does imply "chrome
elements" and "chrome://polymer" does imply "using polymer in Chrome".

If we're against writing a new data source for this that's OK I guess, but if
the only way these things will ever be loaded is via a URL that starts with
chrome:// it seems pretty silly to add 3 more "cr" to it...

[michaelpg, 2015/02/20 01:26:48]

My editor cuts this down to 2s... but I acknowledge that it's repetitive.
Both. And this is one way we reconcile that. This is the convention that has
formed around web components.

Just because we're enforcing Chrome style (- vs _) and making use of Chrome
facilities (e.g. including with "chrome://" instead of relative paths) doesn't
mean we should assume nobody will be interested in using some of our components
in their projects.

Also, we aren't assuming all files will have the same names as their
directories. For instance, "paper-dropdown/paper-dropdown-transition.html" is
used by "paper-dropdown/paper-dropdown.html" (yay composition). But it makes it
clear that:

    paper-dropdown/paper-dropdown.html
    paper-dropdown/paper-dropdown-transition.html

both belong to paper-dropdown, while

    paper-dropdown-menu/paper-dropdown-menu.html

belongs to the separate paper-dropdown-menu component. I don't see a great way
to encode that information while saving a substantial number of characters... we
could leave out "cr_" in the leaf directories.
I meant that "using elements in chrome" is not the same as "using custom
elements in chrome that are specific to chrome rather than a third party". If
"Polymer" can be top-level, Chrome elements should go in a "Chrome" top-level
"directory", thus "polymer" and "cr_elements".

I don't care much though, so "chrome://elements" is fine with me.
Not sure what you mean, we added this to shared_resources_data_source rather
than create a new data source, but it's easily changeable either way.

+
+<polymer-element name="cr-checkbox">
+  <template>
+    <link rel="stylesheet" href="cr_checkbox.css">
+    <cr-events id="events"></cr-events>
+    <paper-checkbox id="checkbox"
+        checked?="{{ checked }}" disabled?="{{ disabled }}" label="{{ label }}">
+    </paper-checkbox>
+  </template>
+  <script src="cr_checkbox.js"></script>
+</polymer-element>