[Storage] Blob Storage Refactoring pt 1:

[chromium-blink-merge.git] / chrome / common / extensions / docs / templates / articles / single_purpose.html

<h1>Extensions Quality Guidelines FAQ</h1>

<h2 id="one">1.) What is the new policy?</h2>

<p>
To maintain the quality of the Chrome user experience,
we recently launched a new policy requiring Chrome extensions
to have a single purpose.
We are also introducing the new
<a href="http://blog.chromium.org/2014/03/protecting-user-settings-on-windows.html">Settings Override API</a>
to allow extensions to manage important Chrome settings on Windows.
Beginning with the July release of Chrome,
the Settings Override API will be the only approved path
for offering settings changes to Chrome users on Windows.
In addition, starting with the May 20, 2014 release of Chrome,
we <a href="http://blog.chromium.org/2014/02/make-sure-to-get-your-extension-in.html">have begun to require</a>
that extensions in Chrome for Windows be hosted in the Chrome Web Store.
</p>

<h2 id="two">2.) Why did Google launch a “single purpose” Chrome extensions policy?</h2>

<p>For an overview of the policy announcement, please read this
<a href="http://blog.chromium.org/2013/12/keeping-chrome-extensions-simple.html">Chromium blog post</a>.</p>

<p>We launched this policy because
multi-purpose extensions can crowd your browser UI
and slow down your web browsing - sometimes significantly.
Speed and simplicity have always been part of Chrome's core principles,
so this policy will help us get back to the design that was originally intended.
Also, unexpected changes to browser functionality and
settings have become the number one user complaint for Chrome users,
and this policy helps minimize the problem by ensuring
that users understand what extensions are doing.
</p>

<h2 id="three">3.) Where can I find the “single purpose” policy?</h2>

<p>
Please refer to the
<a href="https://developer.chrome.com/webstore/program_policies?csw=1#extensions">Extensions Quality Guidelines</a>
section of the Chrome Web Store Developer Program Policies.
</p>

<h2 id="four">4.) What does “single purpose” actually mean?</h2>

<p>
“Single purpose” can refer to one of two aspects of an extension: 
</p>

<p>
An extension can have a single purpose limited to a narrow
<strong>focus area or subject matter</strong>
(for example, news headlines", "weather", "comparison shopping").
If the extension has a narrow focus area or subject matter,
then it can offer various functions related
to that focus area or subject matter.
For example, a news headlines extension could have a browser action button
that allows users to see news stories and replace the new tab page
with news-only content,
so long as all of those functions are narrowly focused
on the news headline focus area. 
</p>

<p>
Or, an extension can have a single purpose limited
to a narrow <strong>browser function</strong>
(for example, "new tab page", "tab management", or "browser history").
If the extension is implemented in a single function,
then it can offer content or features related to different areas or subjects.
For example, an extension that replaces the new tab page could offer
multiple unrelated features on the new tab page
(for example, weather forecast, news headlines, search engine, and so on),
but it can’t also provide a browser action button,
change the browser’s homepage, or
make any other changes to browser functionality.
</p>

<h2 id="five">5.) Will this policy affect my extension?</h2>

<p>
It depends.
Particularly if your extension offers multiple features,
please make sure that it has a single purpose.
Ask yourself these questions:
</p>

<ul>
  <li>Does my extension have a narrow focus area
  or a narrow function as described above?</li>
  <li>If my extension has a narrow focus area,
  are all of the features directly related to that single purpose?</li>
  <li>If my extension has multiple features,
  does it only affect a narrow function of the browser?</li>
  <li>Does my extension modify Chrome’s behavior in a predictable way,
  in line with the extension's narrow, stated purpose?</li>
</ul>

<p>
If you’re unsure, you can email
<a href="mailto:chromewebstore-policy@google.com">chromewebstore-policy@google.com</a>
with your extension ID,
and we’ll take a look and try to provide feedback within a week.
If your extension does not have a single purpose,
then you will need to remove functionality
or split your extension into different extensions. 
</p>

<h2 id="six">6.) What will happen
if I don’t make my extension compliant with this policy?</h2>

<p>
If you created your extension after December 19, 2013,
your extension will not be permitted in the Chrome Web Store.
If you created your extension prior to December 19,2013,
your extension may be removed from the Chrome Web Store starting July 22, 2014,
although you will still be able to update the extension and file appeals.
Please keep in mind that
your re-published item will not be immediately published live in the store.
The re-published item will undergo a compliance review
before it can be restored.
</p>

<p>
In order to minimize disruption for users,
we recommend that you take a moment to carefully review your extensions
and make necessary updates as soon as possible.
You can email us at
<a href="mailto:chromewebstore-policy@google.com">chromewebstore-policy@google.com</a>
with your extension ID, and we’ll try to provide feedback within a week.
</p>

<h2 id="seven">7.) Can my extension make changes to the start page,
homepage, and new tab settings?</h2>

<p>
Yes.
If the purpose of your extension is to modify one narrow function
of the browser (either the start page, homepage or new tab page, for example),
and it does only that, then it would be compliant with the single-purpose policy.
Additionally, if the purpose of your extension is limited
to one focus area or subject matter,
then you can have various functions related to that one area or subject matter,
including changes to start page, homepage and new tab page. 
</p>

<p>
Beginning with the July release of Chrome,
the only way to programmatically change the homepage, search provider,
and startup page settings in Chrome on Windows will be via an extension
that uses the Settings Override API.
Where more than one extension modifies these Chrome settings,
the most recently installed extension will manage the settings it has modified
via the Settings Override API.
Extension developers can modify the new tab page
(and a few other Chrome pages) using the same
<a href="https://developer.chrome.com/extensions/override">override method</a>
as before. 
</p>

<p>
In addition,
if you want to publish an extension that modifies Chrome settings,
you must either control any domains you wish to set in any changed browser settings
or redistribute an extension created by the entity that controls those domains.
For example, you could distribute an extension that changes the homepage
to wikipedia.org if the Wikimedia Foundation originally created and
published the extension in the Chrome Web Store,
and gave you the right to distribute it.
</p>

<p>
Please see this
<a href="http://blog.chromium.org/2014/03/protecting-user-settings-on-windows.html">Chromium blog post</a>
for more information.
</p>

<h2 id="eight">8.) Can my extension make changes to the default search settings?</h2>

<p>
Yes.
If the only purpose of the extension is to change the default search settings,
then it would be compliant with the single purpose policy.
Additionally,
if the single purpose of your extension is search as the narrow focus area,
and nothing else, then you can offer various functions related to search,
including changes to default search settings.
</p>

<h2 id="nine">9.) How will users be notified of settings changes in new versions of Chrome?</h2>

<p>
If an extension changes Chrome settings via the Settings Override API,
the user will be notified of the settings changes prior to installation,
when they encounter the settings change for the first time,
and via an indicator next to each changed setting on the Chrome settings page.
From these notifications,
users will have the option to reverse the settings changes
by disabling the extension.
</p>

<h2 id="10">10.) What happens to settings when an extension is disabled?</h2>

<p>
All Chrome settings changed by an extension will be reverted
when that extension is disabled.
All other settings
(for example, those changed directly by a Windows binary)
will remain unchanged.
</p>

<h2 id="eleven">11.) Will users’ existing homepage, search provider or
startup pages be affected by the introduction of the Settings Override API?</h2>

<p>
No.
A user’s existing homepage, search provider or startup settings will
remain unchanged by the introduction of Settings Override API.
Following the launch of the Settings Override API,
only extensions can programmatically change these settings and
only through the Settings Override API.
But all changes to a user’s homepage, search provider or
startup pages made prior to the launch of the Settings Override API,
including any that may have been made by Windows binaries,
will remain unchanged until the user manually updates those settings or
installs an extension that uses the Settings Override API to change them. 
</p>

<h2 id="twelve">12.) Is this new policy Windows-only?</h2>

<p>
The <a href="https://developer.chrome.com/extensions/hosting_changes">requirement</a>
that Chrome extensions be hosted in the Chrome Web Store
initially applies only to Windows extensions.
Likewise, the new Settings Override API will initially be made available
only on Chrome for Windows.
However, the single-purpose policy will apply to all Chrome extensions.
</p>

<h2 id="thirteen">13.) Does this policy apply to Chrome apps too?</h2>

<p>
At this time, Chrome apps (as distinguished from extensions)
are not required to be distributed through the Chrome Web Store,
or to have a single purpose.
Chrome apps are currently not capable of changing Chrome settings.
</p>

<h2 id="fourteen">14.) Can I bundle ad injection with some other type of functionality?</h2>

<p>
No.
This violates the single purpose policy.
However, if injecting ads is the single purpose of the extension and
the extension is otherwise compliant with Chrome policies,
then it would be acceptable.
For example, a “related articles” extension that adds sponsored links
to articles related to a page the user is visiting would be compliant
with the single purpose policy because it has a single purpose limited
to a narrow function of the browser.
You also might want to explore the other monetization options described
<a href="https://developer.chrome.com/webstore/money">here</a>.
</p>

<h2 id="fifteen">15.) Are toolbars permitted under this policy?</h2>

<p>
It depends on what the toolbar does.
As described in
<a href="#four">answer #4</a>,
it must adhere to the narrow single purpose of the extension.
Broad, multi-purpose toolbars are not allowed and
toolbars that are implemented using content scripts
to inject UI into every page are not recommended because
they slow down every page load, clutter the UI,
and can lead to security problems for users.
Instead, consider using a
<a href="https://developer.chrome.com/extensions/browserAction">browser action popup</a>,
which was designed to solve this very problem.
It's a better user experience, with no performance or security downsides.
</p>

<h2 id="sixteen">16.) What will happen to non-compliant extensions
that were already installed by users?</h2>

<p>
All extensions will need to comply with the Extension Quality Guidelines.
If a user installed a non-compliant extension,
then you will need to update them to a compliant extension
that is hosted in the Chrome Web Store.
If the user is not updated to a compliant extension
that is hosted in the Chrome Web Store,
then the extension will be automatically disabled.
As noted above,
any settings or behaviours controlled by the extension,
including any settings controlled by the Settings Override API,
will be reverted when the extension is disabled. 
You can find more information
<a href="http://blog.chromium.org/2014/02/make-sure-to-get-your-extension-in.html">here</a>.
</p>

<h2 id="seventeen">17.) If my extension is rejected from the Chrome Web Store
because it doesn’t comply with the single purpose policy,
what will happen after the requirement to host extensions
in the Chrome Web Store comes into effect?</h2>

<p>
If your extension is rejected from the Chrome Web Store,
you will need to make changes or appeal the decision.
After the requirement to host extensions
in the Chrome Web Store comes into effect in late May 2014,
your extension must be hosted in the Chrome Web Store or
it will be automatically disabled from the users’ browsers. 
</p>

<h2 id="eighteen">18.) If my extension gets flagged for review under the single purpose policy,
what will happen?</h2>

<p>
Our team will review it,
and it may be removed from the Chrome Web Store.
You’ll have a chance to make changes and appeal the decision.
As noted above,
if you created your extension before we announced the policy on December 19, 2013,
you have until July 22, 2014 to make changes.
If your extension was created after the policy was announced,
it needs to be compliant now.
You can temporarily unpublish it and contact us at
<a href="mailto:chromewebstore-policy@google.com">chromewebstore-policy@google.com</a>
with your extension ID if you’d like feedback.
We’ll try to respond within a week.
</p>

<h2 id="nineteen">19.) I need help. Who should I contact?</h2>

<p>
You can email
<a href="mailto:chromewebstore-policy@google.com">chromewebstore-policy@google.com</a>
with your extension ID,
and we’ll take a look and try to provide feedback within a week.
This is a lightweight review intended to give you an indication
of whether your extension will comply with the new policy.
</p>

<h2 id="appendix">Appendix: Examples of extensions that comply with the quality guidelines</h2>

<p>
An extension that adds features to Chrome’s browser history.
All of the features are contained in a single browser function.
</p>

<img src="{{static}}/images/history-extension.png"
     width="680"
     height="385"
     alt="Image of browsing history extension">

<p>
An extension with a single subject matter:
It provides dropdown information about the weather.
Because it is focused on one type of content,
this extension could also change browser settings, like the new tab page,
where the extension displays weather conditions and offers a weather search.
</p>

<img src="{{static}}/images/extension.png"
     width="680"
     height="425"
     alt="Image of weather extension">

<img src="{{static}}/images/search-extension2.png"
     width="680"
     height="425"
     alt="Image of weather extension showing new tab page">

<p>
A search extension.
It has multiple features, including this dropdown,
but all of them are related to the narrow subject matter of search.
</p>

<img src="{{static}}/images/extension2.png"
     width="680"
     height="425"
     alt="Image of search extension">