Remove IME surface when hidden

When IME is no longer shown, notify IMS to hide the window surface.
This reclaims the memory allocated to IME window surface.

Fix: 150163310
Test: atest CtsInputMethodTests
      Manually:
      1. Open any app that has editor  and run
         adb shell  dumpsys SurfaceFlinger | grep Total
      2. Note down total memory
      3. Tap on editor and IME shows. Note down memory
         using command in #1. It should go up by ~27MB
      4. Hide IME and note down memory again.
         It should revert to original value in #1.

Change-Id: I6c2a13dd40b22d3fd62b4763ba369992e5ff1138

1 files changed, 15 insertions, 0 deletions

diff --git a/core/java/android/inputmethodservice/InputMethodService.java b/core/java/android/inputmethodservice/InputMethodService.java
index 20a4ab35defec..61adfbce30bff 100644
--- a/core/java/android/inputmethodservice/InputMethodService.java
+++ b/core/java/android/inputmethodservice/InputMethodService.java
@@ -814,6 +814,13 @@ public class InputMethodService extends AbstractInputMethodService {
         onPreRenderedWindowVisibilityChanged(false /* setVisible */);
     }
 
+    private void removeImeSurface() {
+        if (!mShowInputRequested && !mWindowVisible) {
+            // hiding a window removes its surface.
+            mWindow.hide();
+        }
+    }
+
     private void setImeWindowStatus(int visibilityFlags, int backDisposition) {
         mPrivOps.setImeWindowStatus(visibilityFlags, backDisposition);
     }
@@ -932,6 +939,14 @@ public class InputMethodService extends AbstractInputMethodService {
         public final void notifyImeHidden() {
             InputMethodService.this.notifyImeHidden();
         }
+
+        /**
+         * Notify IME that surface can be now removed.
+         * @hide
+         */
+        public final void removeImeSurface() {
+            InputMethodService.this.removeImeSurface();
+        }
     }
     
     /**