Hide modal permission prompts on Android upon tab navigation/destruction

chrome/android/java/src/org/chromium/chrome/browser/permissions/PermissionDialogController.java

Index: chrome/android/java/src/org/chromium/chrome/browser/permissions/PermissionDialogController.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/permissions/PermissionDialogController.java b/chrome/android/java/src/org/chromium/chrome/browser/permissions/PermissionDialogController.java
index d38dc9b3f037a8e1b40ff6c7ab74d08d726a0701..a4aec34a85852a353d4406f844a7eacf7024b291 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/permissions/PermissionDialogController.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/permissions/PermissionDialogController.java
@@ -89,6 +89,7 @@ public class PermissionDialogController implements AndroidPermissionRequester.Re
      */
     private void queueDialog(PermissionDialogDelegate delegate) {
         mRequestQueue.add(delegate);
+        delegate.setDialogController(this);
         scheduleDisplay();
     }
 
@@ -101,6 +102,11 @@ public class PermissionDialogController implements AndroidPermissionRequester.Re
         return mDialog;
     }
 
+    @VisibleForTesting
+    public int getQueueLengthForTesting() {
+        return mRequestQueue.size();
+    }
+
     @Override
     public void onAndroidPermissionAccepted() {
         mDialogDelegate.onAccept(mSwitchView.isChecked());
@@ -196,6 +202,7 @@ public class PermissionDialogController implements AndroidPermissionRequester.Re
                 // For some reason this is ocassionally null. See crbug.com/708562.
                 if (mDialogDelegate == null) {
                     scheduleDisplay();
+                    return;
                 }
 
                 mDialog = null;
@@ -253,6 +260,18 @@ public class PermissionDialogController implements AndroidPermissionRequester.Re
         return fullString;
     }
 
+    public void destroyFromNative(PermissionDialogDelegate delegate) {

[dominickn, 2017/05/24 03:33:38]

Nit: I would call this dismissFromNative. "Destroy" is more used for Java
calling C++ destructors.

[Timothy Loh, 2017/05/24 04:59:33]

Done.

+        if (mDialogDelegate == delegate) {

[dominickn, 2017/05/24 03:33:38]

Maybe compare the native pointer to be safe.

[Timothy Loh, 2017/05/24 04:59:33]

Not sure what you want, do you mean that the C++ PDD should pass itself to the
dismiss function on the Java PDD?

+            mDialogDelegate = null;
+            AlertDialog dialog = mDialog;

[dominickn, 2017/05/24 03:33:38]

Nit: is it problematic to do:

mDialog.dismiss();
mDialog = null;

[Timothy Loh, 2017/05/24 04:59:33]

Probably not but I think we end up in a weird state because scheduleDisplay()
won't end up dequeueing any requests. It shouldn't matter since any queued
requests are gonna get removed anyway, but it seems odd.

+            mDialog = null;
+            dialog.dismiss();
+        } else {
+            assert mRequestQueue.contains(delegate);

[dominickn, 2017/05/24 03:33:38]

I don't think remove() fails if delegate isn't in the list. Maybe this assert
isn't necessary.

[Timothy Loh, 2017/05/24 04:59:33]

I added it as a sanity check because remove() doesn't fail.

+            mRequestQueue.remove(delegate);
+        }
+    }
+
     private void destroyDelegate() {
         mDialogDelegate.destroy();
         mDialogDelegate = null;