New Getting started example for extensions

chrome/common/extensions/docs/templates/articles/getstarted.html

 <h1>Getting Started: Building a Chrome Extension</h1>
 
 <p>
   Extensions allow you to add functionality to Chrome without diving deeply
   into native code. You can create new extensions for Chrome with those core
   technologies that you're already familiar with from web development: HTML,
   CSS, and JavaScript. If you've ever built a web page, you should feel right at
   home with extensions pretty quickly; we'll put that to the test right now by
-  walking through the construction of a simple extension that will give you
-  one-click access to pictures of kittens. Kittens!
+  walking through the construction of a simple extension that will fetch an
+  image from Google using the current page's URL as search term.

[mkearney1, 2015/01/07 22:30:23]

"as search term" should be "as a search term".

[robwu, 2015/01/07 23:40:54]

Done.

 </p>
 
 <p>
   We'll do so by implementing a UI element we call a
   <a href="browserAction">browser action</a>, which allows us to place a
   clickable icon right next to Chrome's Omnibox for easy access. Clicking that
-  icon will open a popup window filled with kittenish goodness, which will look
-  something like this:
+  icon will open a popup window filled with an image derived from the current
+  page, which will look something like this:
 </p>
 
-<img src="{{static}}/images/gettingstarted-1.jpg"
-     width="600"
-     height="420"
-     alt="Chrome, with an extension's popup open and displaying many kittens.">
+<img src="{{static}}/images/gettingstarted-preview"
+     width="558"
+     height="264"
+     alt="Chrome with an extension's popup open.">
 
 <p>
   If you'd like to follow along at home (and you should!), create a shiny new
   directory on your computer, and pop open your favourite text editor. Let's get
   going!
 </p>
 
 <h2 id="declaration">Something to Declare</h2>
 
 <p>
   The very first thing we'll need to create is a <dfn>manifest file</dfn> named
-  <code>manifest.json</code>. The manifest is nothing more than a JSON-formatted
-  table of contents, containing properties like your extension's name and
-  description, its version number, and so on. At a high level, we'll use it to
+  <code>manifest.json</code>. This manifest is nothing more than a metadata file
+  in JSON format that contains properties like your extension's name,
+  description, version number and so on. At a high level, we will use it to
   declare to Chrome what the extension is going to do, and what permissions it
-  requires in order to do those things.
+  requires in order to do those things. To learn more about the manifest, read
+  the <a href="manifest">documentation of manifest.json</a>.

[mkearney1, 2015/01/07 22:30:23]

Instead of "documentation of manifest.json", replace with doc's actual title:
"Manifest File Format documentation".

[robwu, 2015/01/07 23:40:54]

Done.

 </p>
 
 <p>
-  In order to display kittens, we'll want to tell Chrome that we'd like to
-  create a browser action, and that we'd like free-reign to access kittens from
-  a particular source on the net. A manifest file containing those instructions
-  looks like this:
+  For our example, we will declare a <a href="browserAction">browser action</a>,

[mkearney1, 2015/01/07 22:30:23]

Replace "For our example" with "In our example's manifest".

[robwu, 2015/01/07 23:40:54]

Done.

+  the <a href="activeTab">activeTab permission</a> to see the URL of the current
+  tab, and the host <a href="declare_permissions">permission</a> to access the
+  external Google Image search API.
 </p>
 
 <pre data-filename="manifest.json">
 {
   "manifest_version": 2,
 
-  "name": "One-click Kittens",
-  "description": "This extension demonstrates a browser action with kittens.",
+  "name": "Getting started example",
+  "description": "This extension shows a Google Image search result for the current page",
   "version": "1.0",
 
-  "permissions": [
-    "https://secure.flickr.com/"
-  ],
   "browser_action": {
     "default_icon": "icon.png",
     "default_popup": "popup.html"
-  }
+  },
+  "permissions": [

[mkearney1, 2015/01/07 22:30:23]

Add comments in the sample code that call out the above-mentioned items in the
manifest.

[robwu, 2015/01/07 23:40:54]

Done.

[mkearney1, 2015/01/08 23:00:34]

I still don't see the comments. Weird.
On 2015/01/07 22:30:23, mkearney1 wrote:

[robwu, 2015/01/08 23:09:03]

I added a comment to popup.html that explained the relation between popup.html
and the manifest file.

I'm a bit hesitant with adding comments to manifest.json, because although
Chrome loads such JSON files just fine, the Chrome Web Store used to reject
manifest.json if it is not strict JSON (as defined by json.org), which means
that comments are not supported (https://crbug.com/172863#c9). I don't know
whether this restriction still exists, but since comments are not a part of
standard JSON, I'm not too keen on adding it to the JSON file.

[robwu, 2015/01/14 16:09:19]

I just tested again (14 jan 2015), and the Chrome Web Store still rejects
extensions with comments in manifest.json (// and /* */).

+    "activeTab",
+    "https://ajax.googleapis.com/"
+  ]
 }
 </pre>
 
 <p>
   Go ahead and save that data to a file named <code>manifest.json</code> in the
   directory you created, or
   <a href="examples/tutorials/getstarted/manifest.json" download="manifest.json">
     download a copy of <code>manifest.json</code> from our sample repository
   </a>.
 </p>
 

[mkearney1, 2015/01/07 22:30:23]

Is there a reason you dropped line-by-line breakdown of the manifest? I find it
helpful for beginners.

[robwu, 2015/01/07 23:40:54]

name/description/version are obvious. The first thing that the user sees when
they load the extension is - name, description and version.

The meaning of browser_action is also obvious, because the paragraph before this
code section announces that the tutorial is going to show a browser action, and
the section after the manifest file explains the meaning of the keys within
browser_action.

The permissions section and the specific values are also explained in the
paragraph before this code snippet.

The only thing that is not explicitly explained any more is "manifest_version".
If users are really curious about this field, they can click on the link to the
manifest reference that was just shown before the previous paragraph.

-<h3 id="manifest">What does it mean?</h3>
-
-<p>
-  The attribute names are fairly self-descriptive, but let's walk through the
-  manifest line-by-line to make sure we're all on the same page.
-</p>
-
-<p>
-  The first line, which declares that we're using version 2 of the manifest file
-  format, is mandatory (version 1 is old, deprecated, and generally not
-  awesome).
-</p>
-
-<p>
-  The next block defines the extension's name, description, and version. These
-  will be used both inside of Chrome to show a user which extensions you have
-  installed, and also on the Chrome Web Store to display your extension to
-  potentially new users. The name should be short and snappy, and the
-  description no longer than a sentence or so (you'll have more room for a
-  detailed description later).
-</p>
-
-<p>
-  The final block first requests permission to work with data on
-  <code>https://secure.flickr.com/</code>, and declares that this extension
-  implements a browser action, assigning it a default icon and popup in the
-  process.
-</p>
-
 <h2 id="resources">Resources</h2>
 
 <p>
   You probably noticed that <code>manifest.json</code> pointed at two resource
   files when defining the browser action: <code>icon.png</code> and
   <code>popup.html</code>. Both resources must exist inside the extension
   package, so let's create them now:
 </p>
 
 <ul class="imaged">
   <li>
     <p>
       <img src="{{static}}/images/gettingstarted-icon.png"
            width="127"
            height="127"
+           style="float:right"
            alt="The popup's icon will be displayed right next to the Omnibox.">
       <code>icon.png</code> will be displayed next to the Omnibox, waiting for
-      user interaction. Download a copy of icon.png from our sample repository,
+      user interaction.
       <a href="examples/tutorials/getstarted/icon.png" download="icon.png">
         Download a copy of <code>icon.png</code> from our sample repository
       </a>, and save it into the directory you're working in. You could also
       create your own if you're so inclined; it's just a 19px-square PNG file.
     </p>
   </li>
   <li>
     <p>
-      <img src="{{static}}/images/gettingstarted-popup.jpg"
-           width="165"
-           height="200"
-           alt="The popup's HTML will be rendered directly below the icon when clicked.">
       <code>popup.html</code> will be rendered inside the popup window that's
       created in response to a user's click on the browser action. It's a
       standard HTML file, just like you're used to from web development, giving
       you more or less free reign over what the popup displays.
       <a href="examples/tutorials/getstarted/popup.html" download="popup.html">
         Download a copy of <code>popup.html</code> from our sample repository
-      </a>, and save it into
-      the directory you're working in.
+      </a>, and save it into the directory you're working in.
     </p>
     <p>
-      <code>popup.html</code> requires an additional JavaScript file in order to
-      do the work of grabbing kitten images from the web and loading them into
-      the popup. To save you some effort, just
+      The actual logic of rendering the content of the popup is implemented by
+      <a href="examples/tutorials/getstarted/popup.js">popup.js</a>. You are
+      encouraged to read the elaborate comments in this file to learn more
+      about the logic.<br>
       <a href="examples/tutorials/getstarted/popup.js" download="popup.js">
-        download a copy of <code>popup.js</code> from our sample repository
+        Download a copy of <code>popup.js</code> from our sample repository
       </a>, and save it into the directory you're working in.
     </p>
   </li>
 </ul>
 
 <p>
   You should now have four files in your working directory:
   <a href="examples/tutorials/getstarted/icon.png" download="icon.png"><code>icon.png</code></a>,
   <a href="examples/tutorials/getstarted/manifest.json" download="manifest.json"><code>manifest.json</code></a>,
   <a href="examples/tutorials/getstarted/popup.html" download="popup.html"><code>popup.html</code></a>,
@@ skipping 11 matching lines @@
 </p>
 
 <ol>
   <li>
     <p>
       Visit <code>chrome://extensions</code> in your browser (or open up the
       Chrome menu by clicking the icon to the far right of the Omnibox:
       <img src="{{static}}/images/hotdogmenu.png"
            height="29"
            width="29"
            alt="The menu's icon is three horizontal bars.">. and

[mkearney1, 2015/01/07 22:30:24]

Remove unnecessary period after "> and before and. It's been lingering there for
awhile!

[robwu, 2015/01/07 23:40:54]

Done.

       select <strong>Extensions</strong> under the <strong>Tools</strong> menu
       to get to the same place).
     </p>
   </li>
   <li>
     <p>
       Ensure that the <strong>Developer mode</strong> checkbox in the top
       right-hand corner is checked.
     </p>
   </li>
@@ skipping 20 matching lines @@
   If the extension is valid, it'll be loaded up and active right away! If it's
   invalid, an error message will be displayed at the top of the page. Correct
   the error, and try again.
 </p>
 
 <h2 id="update-code">Fiddle with Code</h2>
 
 <p>
   Now that you've got your first extension up and running, let's fiddle with
   things so that you have an idea what your development process might look like.
-  As a trivial example, let's change the data source to search for pictures of
-  puppies instead of kittens.
+  <br>

[mkearney1, 2015/01/07 22:30:23]

Remove this <br>.

[robwu, 2015/01/07 23:40:54]

Done.

+  For example, let's set a tooltip on the browser action button. According to

[mkearney1, 2015/01/07 22:30:23]

End paragraph after "For example, let's set a tooltip on the browser action
button." And then start a new paragraph with "According to...".

[robwu, 2015/01/07 23:40:54]

Done.

+  the browserAction documentation, tooltips can be set by specifying the
+  <code>default_title</code> key in the manifest file. So open

[mkearney1, 2015/01/07 22:30:23]

Remove 'So' and start sentence with 'Open'.

[robwu, 2015/01/07 23:40:54]

Done.

+  <code>manifest.json</code>, and add this property to <code>browser_action</code>.

[mkearney1, 2015/01/07 22:30:23]

Change 'this property' to 'the default_title to the'.

[robwu, 2015/01/07 23:40:54]

Done.

+  Make sure that the JSON is valid, so quote the key and add a comma where necessary.
+</p>
+
+<pre data-filename="manifest.json">
+{
+  ...
+  "browser_action": {
+    "default_icon": "icon.png",
+    "default_popup": "popup.html",
+    "default_title": "Click here!"
+  },
+  ...
+}
+</pre>
+
+<p>
+  The manifest file is only parsed when the extension is loaded. If you want to
+  see the previous changes in action, the extension has to be reloaded. This can

[mkearney1, 2015/01/07 22:30:23]

The last two sentences in this paragraph are wordy and a bit buggy. Also, I
don't see a Reload button for the entire extensions page. Can we make this very
simple?

How about: Visit the extensions page (go to chrome://extensions or select
Tools>Extensions under the Chrome menu)and click Reload under your extension.

[robwu, 2015/01/07 23:40:54]

At the left of the omnibox.
I've made this paragraph a bit more concise:

https://codereview.chromium.org/732943002/diff2/60001:80001/chrome/common/ext...

+  be done by visiting the extension page
+  (<strong>chrome://extensions</strong>, or
+  <strong>Tools &gt; Extensions</strong> under the Chrome menu), and clicking
+  <strong>Reload</strong> under your extension. The extension can can also be
+  reload by reloading the extension page, e.g. by clicking on the reload button,
+  or by hitting <kbd>F5<kbd> or <kbd>Ctrl</kbd>-<kbd>R</kbd>.
 </p>
 
 <p>
-  Hop into <code>popup.js</code>, and edit line 11 from
-  <code>var QUERY = 'kittens';</code> to read
-  <code>var QUERY = 'puppies';</code>, and save your changes.
-</p>
+  Once you've reloaded the extension, hover over the browser action badge to see
+  the new tooltip!<br>
+  <img src="{{static}}/images/gettingstarted-tooltip-before.png"
+       width="160"
+       height="120"
+       alt="&quot;Getting started example&quot; tooltip.">
 
-<p>
-  If you click on your extension's browser action again, you'll note that your
-  change hasn't yet had an effect. You'll need to let Chrome know that something
-  has happened, either explicitly by going back to the extension page
-  (<strong>chrome://extensions</strong>, or
-  <strong>Tools &gt; Extensions</strong> under the Chrome menu), and clicking
-  <strong>Reload</strong> under your extension, or by reloading the extensions
-  page itself (either via the reload button to the left of the Omnibox, or by
-  hitting F5 or Ctrl-R).
-</p>
-
-<p>
-  Once you've reloaded the extension, click the browser action icon again.
-  Puppies galore!
+  <img src="{{static}}/images/gettingstarted-tooltip-after.png"
+       width="160"
+       height="120"
+       alt="&quot;Click here!&quot; tooltip, after modifying manifest.json and reloading the extension.">
 </p>
 
 <h2 id="next-steps">What next?</h2>
 
 <p>
   You now know about the manifest file's central role in bringing things
-  together, and you've mastered the basics of declaring a browser action, and
-  rendering some kittens (or puppies!) in response to a user's click. That's a
-  great start, and has hopefully gotten you interested enough to explore
-  further. There's a lot more out there to play around with.
+  together, and you've mastered the basics of declaring a browser action.
+  That's a great start, and has hopefully gotten you interested enough to
+  explore further. There's a lot more out there to play around with.
 </p>
 
 <ul>
   <li>
     <p>
       The <a href="overview">Chrome Extension Overview</a> backs up a bit,
       and fills in a lot of detail about extensions' architecture in general,
       and some specific concepts you'll want to be familiar with going forward.
       It's the best next step on your journey towards extension mastery.
     </p>
@@ skipping 14 matching lines @@
       walk you through each API in turn.
     </p>
   </li>
   <li>
     <p>
       Finally, the <a href="devguide">developer's guide</a> has dozens of
       additional links to pieces of documentation you might be interested in.
     </p>
   </li>
 </ul>