Expose activity from WindowAndroid.

Changes ActivityWindow to only keep a WeakReference to the Activity to
avoid it preventing an Activity from being GC'd.

BUG=341231

Review URL: https://codereview.chromium.org/171803002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252360 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 37 insertions, 8 deletions

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 0d689a0..bba7fae 100644
--- a/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
+++ b/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
@@ -18,6 +18,7 @@ import android.view.View;
 import org.chromium.ui.UiUtils;
 
 import java.io.ByteArrayOutputStream;
+import java.lang.ref.WeakReference;
 
 /**
  * The class provides the WindowAndroid's implementation which requires
@@ -30,20 +31,23 @@ public class ActivityWindowAndroid extends WindowAndroid {
     private static final int REQUEST_CODE_RANGE_SIZE = 100;
     private static final String TAG = "ActivityWindowAndroid";
 
-    private final Activity mActivity;
+    private final WeakReference<Activity> mActivityRef;
     private int mNextRequestCode = 0;
 
     public ActivityWindowAndroid(Activity activity) {
         super(activity.getApplicationContext());
-        mActivity = activity;
+        mActivityRef = new WeakReference<Activity>(activity);
     }
 
     @Override
     public int showCancelableIntent(PendingIntent intent, IntentCallback callback, int errorId) {
+        Activity activity = mActivityRef.get();
+        if (activity == null) return START_INTENT_FAILURE;
+
         int requestCode = generateNextRequestCode();
 
         try {
-            mActivity.startIntentSenderForResult(
+            activity.startIntentSenderForResult(
                     intent.getIntentSender(), requestCode, new Intent(), 0, 0, 0);
         } catch (SendIntentException e) {
             return START_INTENT_FAILURE;
@@ -55,10 +59,13 @@ public class ActivityWindowAndroid extends WindowAndroid {
 
     @Override
     public int showCancelableIntent(Intent intent, IntentCallback callback, int errorId) {
+        Activity activity = mActivityRef.get();
+        if (activity == null) return START_INTENT_FAILURE;
+
         int requestCode = generateNextRequestCode();
 
         try {
-            mActivity.startActivityForResult(intent, requestCode);
+            activity.startActivityForResult(intent, requestCode);
         } catch (ActivityNotFoundException e) {
             return START_INTENT_FAILURE;
         }
@@ -69,7 +76,9 @@ public class ActivityWindowAndroid extends WindowAndroid {
 
     @Override
     public void cancelIntent(int requestCode) {
-        mActivity.finishActivity(requestCode);
+        Activity activity = mActivityRef.get();
+        if (activity == null) return;
+        activity.finishActivity(requestCode);
     }
 
     @Override
@@ -94,7 +103,13 @@ public class ActivityWindowAndroid extends WindowAndroid {
     @Override
     @Deprecated
     public Context getContext() {
-        return mActivity;
+        return mActivityRef.get();
+    }
+
+    @Override
+    public WeakReference<Activity> getActivity() {
+        // Return a new WeakReference to prevent clients from releasing our internal WeakReference.
+        return new WeakReference<Activity>(mActivityRef.get());
     }
 
     /**
@@ -103,10 +118,12 @@ public class ActivityWindowAndroid extends WindowAndroid {
      */
     @Override
     public byte[] grabSnapshot(int windowX, int windowY, int width, int height) {
+        Activity activity = mActivityRef.get();
+        if (activity == null) return null;
         try {
             // Take a screenshot of the root activity view. This generally includes UI
             // controls such as the URL bar and OS windows such as the status bar.
-            View rootView = mActivity.findViewById(android.R.id.content).getRootView();
+            View rootView = activity.findViewById(android.R.id.content).getRootView();
             Bitmap bitmap = UiUtils.generateScaledScreenshot(rootView, 0, Bitmap.Config.ARGB_8888);
             if (bitmap == null) return null;
 
diff --git a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
index f7938cd..e87f144 100644
--- a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
+++ b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
@@ -4,6 +4,7 @@
 
 package org.chromium.ui.base;
 
+import android.app.Activity;
 import android.app.PendingIntent;
 import android.content.ContentResolver;
 import android.content.Context;
@@ -16,6 +17,7 @@ import android.widget.Toast;
 import org.chromium.base.CalledByNative;
 import org.chromium.base.JNINamespace;
 
+import java.lang.ref.WeakReference;
 import java.util.HashMap;
 
 /**
@@ -156,7 +158,8 @@ public class WindowAndroid {
     }
 
     /**
-     * TODO(nileshagrawal): Stop returning Activity Context crbug.com/233440.
+     * TODO(tedchoc): Delete this method.  Use getActivity() below.
+     *
      * @return Activity context, it could be null. Note, in most cases, you probably
      * just need Application Context returned by getApplicationContext().
      * @see #getApplicationContext()
@@ -167,6 +170,15 @@ public class WindowAndroid {
     }
 
     /**
+     * @return A reference to owning Activity.  The returned WeakReference will never be null, but
+     *         the contained Activity can be null (either if it has been garbage collected or if
+     *         this is in the context of a WebView that was not created using an Activity).
+     */
+    public WeakReference<Activity> getActivity() {
+        return new WeakReference<Activity>(null);
+    }
+
+    /**
      * @return The application context for this activity.
      */
     public Context getApplicationContext() {