Merge "Implement InputConnectionWrapper#takeSnapshot()" into udc-dev

core/java/android/view/inputmethod/InputConnectionWrapper.java

@@ -412,4 +412,32 @@ public class InputConnectionWrapper implements InputConnection {
     public boolean setImeConsumesInput(boolean imeConsumesInput) {
         return mTarget.setImeConsumesInput(imeConsumesInput);
     }
+
+    /**
+     * Called by the system when it needs to take a snapshot of multiple text-related data in an
+     * atomic manner.
+     *
+     * <p><strong>Editor authors</strong>: Supporting this method is strongly encouraged. Atomically
+     * taken {@link TextSnapshot} is going to be really helpful for the system when optimizing IPCs
+     * in a safe and deterministic manner.  Return {@code null} if an atomically taken
+     * {@link TextSnapshot} is unavailable.  The system continues supporting such a scenario
+     * gracefully.</p>
+     *
+     * <p><strong>IME authors</strong>: Currently IMEs cannot call this method directly and always
+     * receive {@code null} as the result.</p>
+     *
+     * <p>Beware that there is a bug that this method was not overridden in
+     * {@link InputConnectionWrapper}, which ended up always returning {@code null} when gets
+     * called even if the wrapped {@link InputConnection} implements this method.  The bug was
+     * fixed in {@link android.os.Build.VERSION_CODES#UPSIDE_DOWN_CAKE}.</p>
+     *
+     * @return {@code null} if {@link TextSnapshot} is unavailable and/or this API is called from
+     *         IMEs. Beware the bug in older devices mentioned above.
+     * @throws NullPointerException if the target is {@code null}.
+     */
+    @Nullable
+    @Override
+    public TextSnapshot takeSnapshot() {
+        return mTarget.takeSnapshot();
+    }
 }