docs: add explanation of default permissions to Permission guide

are sandboxed in the same way and have the same degree of security from each

other.</p>

<a name="signing"></a>

<h2>Application Signing</h2>

<a name="permissions"></a>

<h2>Using Permissions</h2>

<p>A basic Android application has no permissions associated with it,

<p>A basic Android application has no permissions associated with it by default,

meaning it can not do anything that would adversely impact the user experience

or any data on the device.  To make use of protected features of the device,

you must include in your <code>AndroidManifest.xml</code> one or more

</ul>

<div class="caution">

<p><strong>Caution:</strong> Over time,

new restrictions may be added to the platform such that, in order

to use certain APIs, your app must request a permission that it previously did not need.

Because existing apps assume access to those APIs is freely available,

Android may apply the new permission request to the app's manifest to avoid

breaking the app on the new platform version.

Android makes the decision as to whether an app might need the permission based on

the value provided for the <a

href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code targetSdkVersion}</a>

attribute. If the value is lower than the version in which the permission was added, then

Android adds the permission.</p>

<p>For example, the {@link android.Manifest.permission#WRITE_EXTERNAL_STORAGE} permission was

added in API level 4 to restrict access to the shared storage space. If your <a

href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code targetSdkVersion}</a>

is 3 or lower, this permission is added to your app on newer versions of Android.</p>

<p>Beware that if this happens to your app, your app listing on Google Play will show these

required permissions even though your app might not actually require them.</p>

<p>To avoid this and remove the default permissions you don't need, always update your <a

href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code targetSdkVersion}</a>

to be as high as possible. You can see which permissions were added with each release in the

{@link android.os.Build.VERSION_CODES} documentation.</p>

</div>

<a name="declaring"></a>

<h2>Declaring and Enforcing Permissions</h2>

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    /** Instantiate the interface and set the context */

    JavaScriptInterface(Context c) {

    WebAppInterface(Context c) {

        mContext = c;

    }