Hold a reference to any kind of context in WindowAndroid.

ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java

Index: ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
diff --git a/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java b/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
index ad02b45884a08c9467fb8c7ead4a291f31a0a9e4..663c64454a8106619435c9d741bd7edbfa0383c1 100644
--- a/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
+++ b/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
@@ -7,6 +7,7 @@ package org.chromium.ui.base;
 import android.app.Activity;
 import android.app.PendingIntent;
 import android.content.ActivityNotFoundException;
+import android.content.Context;
 import android.content.Intent;
 import android.content.IntentSender.SendIntentException;
 import android.content.SharedPreferences;
@@ -41,7 +42,6 @@ public class ActivityWindowAndroid
 
     private static final String PERMISSION_QUERIED_KEY_PREFIX = "HasRequestedAndroidPermission::";
 
-    private final WeakReference<Activity> mActivityRef;
     private final Handler mHandler;
     private final SparseArray<PermissionCallback> mOutstandingPermissionRequests;
 
@@ -63,8 +63,7 @@ public class ActivityWindowAndroid
      * @param listenToActivityState Whether to listen to activity state changes.
      */
     public ActivityWindowAndroid(Activity activity, boolean listenToActivityState) {
-        super(activity.getApplicationContext());
-        mActivityRef = new WeakReference<Activity>(activity);
+        super(activity);
         mHandler = new Handler();
         mOutstandingPermissionRequests = new SparseArray<PermissionCallback>();
         if (listenToActivityState) {
@@ -76,16 +75,16 @@ public class ActivityWindowAndroid
 
     @Override
     protected void registerKeyboardVisibilityCallbacks() {
-        Activity activity = mActivityRef.get();
+        Activity activity = getActivity().get();
         if (activity == null) return;
         View content = activity.findViewById(android.R.id.content);
-        mIsKeyboardShowing = UiUtils.isKeyboardShowing(mActivityRef.get(), content);
+        mIsKeyboardShowing = UiUtils.isKeyboardShowing(getActivity().get(), content);
         content.addOnLayoutChangeListener(this);
     }
 
     @Override
     protected void unregisterKeyboardVisibilityCallbacks() {
-        Activity activity = mActivityRef.get();
+        Activity activity = getActivity().get();
         if (activity == null) return;
         activity.findViewById(android.R.id.content).removeOnLayoutChangeListener(this);
     }
@@ -93,7 +92,7 @@ public class ActivityWindowAndroid
     @Override
     public int showCancelableIntent(
             PendingIntent intent, IntentCallback callback, Integer errorId) {
-        Activity activity = mActivityRef.get();
+        Activity activity = getActivity().get();
         if (activity == null) return START_INTENT_FAILURE;
 
         int requestCode = generateNextRequestCode();
@@ -111,7 +110,7 @@ public class ActivityWindowAndroid
 
     @Override
     public int showCancelableIntent(Intent intent, IntentCallback callback, Integer errorId) {
-        Activity activity = mActivityRef.get();
+        Activity activity = getActivity().get();
         if (activity == null) return START_INTENT_FAILURE;
 
         int requestCode = generateNextRequestCode();
@@ -128,7 +127,7 @@ public class ActivityWindowAndroid
 
     @Override
     public void cancelIntent(int requestCode) {
-        Activity activity = mActivityRef.get();
+        Activity activity = getActivity().get();
         if (activity == null) return;
         activity.finishActivity(requestCode);
     }
@@ -190,7 +189,7 @@ public class ActivityWindowAndroid
      */
     public boolean onRequestPermissionsResult(int requestCode, String[] permissions,
             int[] grantResults) {
-        Activity activity = mActivityRef.get();
+        Activity activity = getActivity().get();
         assert activity != null;
 
         SharedPreferences.Editor editor =
@@ -209,8 +208,9 @@ public class ActivityWindowAndroid
 
     @Override
     public WeakReference<Activity> getActivity() {
-        // Return a new WeakReference to prevent clients from releasing our internal WeakReference.
-        return new WeakReference<Activity>(mActivityRef.get());
+        Context context = getContext().get();
+        if (context instanceof Activity) return new WeakReference<Activity>((Activity) context);

[Ted C, 2015/11/11 00:19:45]

I would just add a warning suppression and do the cast without the if check.  

If this is ever not the case, then it is a programming mistake that should crash
early and obviously

[boliu, 2015/11/11 00:34:08]

Hmm, not as simple as that. What if context is null? In that case, instanceof
returns false, and the "Should never happen" actually happens.

*However*, I do second crashing if it is non-null and non-Activity, and also
suggest we do that check early in the constructor, rather than here.

[Ted C, 2015/11/11 00:44:25]

We specifically don't care about the null case though right?

You can cast null to any object type without failure, so null being cast to an
Activity (even if the original context was incorrectly the application context
for whatever reason) will still work.

[boliu, 2015/11/11 00:46:29]

Sure. But in that case, should getActivity return null, or
WeakReference<Activity>(null)? I think it should the latter one.

[Ted C, 2015/11/11 00:48:41]

Definitely the latter.

But my original suggestion was that this method simply be:

return new WeakReference<Activity>((Activity) getContext().get());

That will handle either getContext() referencing an activity or null whatever
and crash otherwise.

[boliu, 2015/11/11 01:01:20]

that sgtm

[gsennton, 2015/11/13 20:00:04]

Done.

+        return null; // Should never happen
     }
 
     @Override
@@ -225,7 +225,7 @@ public class ActivityWindowAndroid
     @Override
     public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft,
             int oldTop, int oldRight, int oldBottom) {
-        keyboardVisibilityPossiblyChanged(UiUtils.isKeyboardShowing(mActivityRef.get(), v));
+        keyboardVisibilityPossiblyChanged(UiUtils.isKeyboardShowing(getActivity().get(), v));
     }
 
     private int generateNextRequestCode() {
@@ -251,7 +251,7 @@ public class ActivityWindowAndroid
         public boolean canRequestPermission(String permission) {
             if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) return false;
 
-            Activity activity = mActivityRef.get();
+            Activity activity = getActivity().get();
             if (activity == null) return false;
 
             if (isPermissionRevokedByPolicy(permission)) {
@@ -275,7 +275,7 @@ public class ActivityWindowAndroid
         public boolean isPermissionRevokedByPolicy(String permission) {
             if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) return false;
 
-            Activity activity = mActivityRef.get();
+            Activity activity = getActivity().get();
             if (activity == null) return false;
 
             return activity.getPackageManager().isPermissionRevokedByPolicy(
@@ -311,7 +311,7 @@ public class ActivityWindowAndroid
         private boolean requestPermissionsInternal(
                 String[] permissions, PermissionCallback callback) {
             if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) return false;
-            Activity activity = mActivityRef.get();
+            Activity activity = getActivity().get();
             if (activity == null) return false;
 
             int requestCode = generateNextRequestCode();