DO NOT MERGE Kill most processes when display size changes

This isn't something apps generally can handle, so we kill all of
them for now.

Test: Change cutout overlay that changes display size
Test: Rotate screen
Bug: 112876936
Change-Id: Ic3b0f1b3ae1e9bd93ac8f2c6952aa093878602b8

3 files changed, 27 insertions, 2 deletions

diff --git a/core/java/android/app/ActivityManagerInternal.java b/core/java/android/app/ActivityManagerInternal.java
index 9b6764d96fb2..14cae95508e7 100644
--- a/core/java/android/app/ActivityManagerInternal.java
+++ b/core/java/android/app/ActivityManagerInternal.java
@@ -413,4 +413,9 @@ public abstract class ActivityManagerInternal {
      * @return The intent used to launch the home activity.
      */
     public abstract Intent getHomeIntent();
+
+    /**
+     * WindowManager notifies AM when display size of the default display changes.
+     */
+    public abstract void notifyDefaultDisplaySizeChanged();
 }
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 2861600db52f..ee4bedf37abb 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -26870,6 +26870,21 @@ public class ActivityManagerService extends IActivityManager.Stub
                 return ActivityManagerService.this.getHomeIntent();
             }
         }
+
+        @Override
+        public void notifyDefaultDisplaySizeChanged() {
+            synchronized (this) {
+                if (mSystemServiceManager.isBootCompleted()) {
+                    Slog.i(TAG, "Killing processes because of display size change");
+                    killAllBackgroundProcessesExcept(-1, ActivityManager.PROCESS_STATE_SERVICE);
+
+                    // TODO: Ugly hack to unblock the release
+                    if (mHomeProcess != null) {
+                        removeProcessLocked(mHomeProcess, false, true, "kill home screen size");
+                    }
+                }
+            }
+        }
     }
 
     /**
diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index 2887e5ef9061..2941e93d12dc 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -1775,8 +1775,9 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
         final int newDensity = mDisplayInfo.logicalDensityDpi;
         final DisplayCutout newCutout = mDisplayInfo.displayCutout;
 
-        final boolean displayMetricsChanged = mInitialDisplayWidth != newWidth
-                || mInitialDisplayHeight != newHeight
+        final boolean sizeChanged = mInitialDisplayWidth != newWidth
+                || mInitialDisplayHeight != newHeight;
+        final boolean displayMetricsChanged = sizeChanged
                 || mInitialDisplayDensity != mDisplayInfo.logicalDensityDpi
                 || !Objects.equals(mInitialDisplayCutout, newCutout);
 
@@ -1798,6 +1799,10 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
             mInitialDisplayCutout = newCutout;
             mService.reconfigureDisplayLocked(this);
         }
+
+        if (isDefaultDisplay && sizeChanged) {
+            mService.mH.post(mService.mAmInternal::notifyDefaultDisplaySizeChanged);
+        }
     }
 
     /** Sets the maximum width the screen resolution can be */