android: Register Display lazily

ui/android/java/src/org/chromium/ui/display/DisplayAndroidManager.java

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.ui.display;
 
 import android.annotation.SuppressLint;
 import android.content.ComponentCallbacks;
 import android.content.Context;
 import android.content.res.Configuration;
@@ skipping 134 matching lines @@
 
         @Override
         public void stopAccurateListening() {
             // Always accurate. Do nothing.
         }
 
         // DisplayListener implementation:
 
         @Override
         public void onDisplayAdded(int sdkDisplayId) {
-            addDisplay(getDisplayManager().getDisplay(sdkDisplayId));
+            // DisplayAndroid is added lazily on first use. This is to workaround corner case
+            // bug where DisplayManager.getDisplay(sdkDisplayId) returning null here.
         }
 
         @Override
         public void onDisplayRemoved(int sdkDisplayId) {
             mIdMap.remove(sdkDisplayId);
         }
 
         @Override
         public void onDisplayChanged(int sdkDisplayId) {
             updateDeviceDisplayInfo();
-            mIdMap.get(sdkDisplayId)
-                    .updateFromDisplay(getDisplayManager().getDisplay(sdkDisplayId));
+            DisplayAndroid displayAndroid = mIdMap.get(sdkDisplayId);
+            if (displayAndroid != null) {
+                displayAndroid.updateFromDisplay(getDisplayManager().getDisplay(sdkDisplayId));
+            }
         }
     }
 
     private static DisplayAndroidManager sDisplayAndroidManager;
 
     private SparseArray<DisplayAndroid> mIdMap;
     private final DisplayListenerBackend mBackend;
 
     /* package */ static DisplayAndroidManager getInstance() {
         if (sDisplayAndroidManager == null) {
@@ skipping 19 matching lines @@
     private static DisplayManager getDisplayManager() {
         return (DisplayManager) getContext().getSystemService(Context.DISPLAY_SERVICE);
     }
 
     private static void updateDeviceDisplayInfo() {
         DeviceDisplayInfo.create(getContext()).updateNativeSharedDisplayInfo();
     }
 
     private DisplayAndroidManager() {
         mIdMap = new SparseArray<>();
-
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
             mBackend = new DisplayListenerBackendImpl();
-            for (Display display : getDisplayManager().getDisplays()) {
-                addDisplay(display);
-            }
         } else {
             Display display = getDisplayFromContext(getContext());
             mBackend = new DisplayListenerAPI16(display.getDisplayId());
             addDisplay(display);  // Note this display is never removed.
         }
         mBackend.startListening();
     }
 
-    /* package */ DisplayAndroid getDisplayAndroid(int sdkDisplayId) {
-        return mIdMap.get(sdkDisplayId);
+    /* package */ DisplayAndroid getDisplayAndroid(Display display) {
+        int sdkDisplayId = display.getDisplayId();
+        DisplayAndroid displayAndroid = mIdMap.get(sdkDisplayId);
+        if (displayAndroid == null) {
+            displayAndroid = addDisplay(display);
+        }
+        return displayAndroid;
     }
 
     /* package */ void startAccurateListening() {
         mBackend.startAccurateListening();
     }
 
     /* package */ void stopAccurateListening() {
         mBackend.stopAccurateListening();
     }
 
-    private void addDisplay(Display display) {
+    private DisplayAndroid addDisplay(Display display) {
         int sdkDisplayId = display.getDisplayId();
-        mIdMap.put(sdkDisplayId, new DisplayAndroid(display));
+        DisplayAndroid displayAndroid = new DisplayAndroid(display);
+        mIdMap.put(sdkDisplayId, displayAndroid);
+        return displayAndroid;
     }
 }