App and Extension Documentation: Don't forbid non-standard icon sizes.

Now it explicitly says that apps and extensions may use any size of icon, but
still recommends certain basic sizes, in particular 128x128.

BUG=230281

Review URL: https://chromiumcodereview.appspot.com/14037008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@194776 0039d316-1c4b-4281-b951-d872f2087c98

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

@@ -184,17 +184,11 @@ Here's an example of specifying the icons:
 </pre>
 
 <p class="note">
-<b>Important:</b>
-Use only the documented icon sizes.
-<br><br>
-You might notice that Chrome sometimes resizes these icons down to smaller
-sizes. For example, the install dialog might shrink the 128-pixel
-icon down to 69 pixels.
-<br><br>
-However, the details of
-Chrome's UI may change between versions, and these changes assume that
-developers are using the documented sizes. If you use other sizes,
-your icon may look bad in future versions of the browser.
+You may provide icons of any other size you wish, and Chrome will attempt to use
+the best size where appropriate. For example, Windows often requires 32-pixel
+icons, and if the app includes a 32-pixel icon, Chrome will choose that instead
+of shrinking a 48-pixel icon down. However, you should ensure that all of your
+icons are square, or unexpected behavior may result.
 </p>
 
 <p>