feat(android): Add custom masking options for session replay

Author: romtsn

docs/platforms/android/session-replay/privacy.mdx

@@ -0,0 +1,124 @@
+---
+title: Privacy
+sidebar_order: 5501
+notSupported:
+description: "Learn how to mask parts of your app's data in Session Replay."
+---
+
+<Alert>
+
+Before publising an App with Session Replay enabled, make sure to test it thoroughly to ensure that no sensitive data is exposed.
+
+If you choose to use custom masking in your Session Replays, you may accidentally expose sensitive customer data. Be sure to double-check what you choose to expose.
+
+</Alert>
+
+By default, our Session Replay SDK masks all text content, images, webviews and user input. This helps ensure that no sensitive data will be exposed. You can also manually choose which parts of your app's data you want to mask by using the different options listed below.
+
+To disable the default masking behavior (not to be used on applications with sensitive data):
+
+```kotlin
+options.experimental.sessionReplay.maskAllText = false
+options.experimental.sessionReplay.maskAllImages = false
+```
+
+## Mask by View Class
+
+You can choose which type of view you want to mask or unmask by using the `addMaskViewClass` or `addUnmaskViewClass` options.
+
+Let's say you have:
+- A custom view that you want to mask
+- A `TextView` subclass (which normally would be masked) that you don't want to mask.
+
+You can set the options like this:
+
+```kotlin
+  options.experimental.sessionReplay.addMaskViewClass("com.example.MyCustomView")
+  options.experimental.sessionReplay.addUnmaskViewClass("com.example.MyCustomTextView")
+```
+
+<Note>
+
+If you're using a code obfuscation tool (R8/ProGuard), adjust your proguard rules accordingly so your custom view class names are not minified.
+
+</Note>
+
+### Class Hierarchy
+
+The masking behavior applies to classes and their subclasses. This means if you add a view via `addMaskViewClass` (for example, `TextView`, which is the default behavior), its respective subclasses (`RadioButton`, `CheckBox`, `EditText`, etc.) will also be masked. For example, you can do the following:
+
+```kotlin
+  options.experimental.sessionReplay.addMaskViewClass("android.widget.TextView") // mask TextView and all its subclasses
+  options.experimental.sessionReplay.addUnmaskViewClass("android.widget.RadioButton") // but unmask RadioButton and all its subclasses
+```
+
+## Mask by View Instance
+
+You can also choose to mask or unmask a specific view instance by using tags like this:
+
+```xml
+  <View
+    android:id="@+id/my_view"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:tag="sentry-mask|sentry-unmask"/>
+```
+
+```kotlin
+  view.tag = "sentry-mask|sentry-unmask"
+```
+
+If your view already has a tag assigned, you can set the masking tag by a sentry-specific id:
+
+```xml
+  <View
+    android:id="@+id/my_view"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content">
+    <tag android:id="@id/sentry_privacy" android:value="mask|unmask"/>
+  </View>
+```
+
+```kotlin
+  view.setTag(io.sentry.android.replay.R.id.sentry_privacy, "mask|unmask")
+```
+
+We also provide convenient extension functions for Kotlin:
+
+```kotlin
+  view.sentryReplayMask()
+  // or
+  view.sentryReplayUnmask()
+```
+
+## Jetpack Compose
+
+We only support masking specific composables in Jetpack Compose. Since composables don't have a concept of classes (they are all composable functions), masking by view class is not supported.
+
+In this example, we want the "Hello" message to be captured in the replay (by default, all text composables are masked), but not the custom composable:
+
+```kotlin
+import io.sentry.android.replay.sentryReplayMask
+import io.sentry.android.replay.sentryReplayUnmask
+
+Column(
+  verticalArrangement = Arrangement.Center,
+  horizontalAlignment = Alignment.CenterHorizontally,
+  modifier = Modifier.fillMaxSize()
+) {
+  MyCustomComposable(
+    modifier = Modifier.sentryReplayMask()
+    ...
+  )
+  Text("Hello", modifier = Modifier.sentryReplayUnmask())
+}
+```
+
+Currently, we don't support masking anything within embedded android views (`AndroidView`), but you can still mask the entire view as follows:
+
+```kotlin
+AndroidView(
+  modifier = Modifier.sentryReplayMask(),
+  factory = { context -> ... }
+)
+```