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..fcb0b97720223e83e05dfcaf40bb90f6da28f6c8 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());
@@ -193,9 +199,10 @@ public class PermissionDialogController implements AndroidPermissionRequester.Re
         mDialog.setOnDismissListener(new DialogInterface.OnDismissListener() {
             @Override
             public void onDismiss(DialogInterface dialog) {
-                // For some reason this is ocassionally null. See crbug.com/708562.
+                // Null if dismiss initiated by C++, or for some unknown reason (crbug.com/708562).
                 if (mDialogDelegate == null) {
                     scheduleDisplay();
+                    return;
                 }
 
                 mDialog = null;
@@ -253,6 +260,19 @@ public class PermissionDialogController implements AndroidPermissionRequester.Re
         return fullString;
     }
 
+    public void dismissFromNative(PermissionDialogDelegate delegate) {
+        if (mDialogDelegate == delegate) {
+            mDialogDelegate = null;
+            AlertDialog dialog = mDialog;
+            mDialog = null;
+            dialog.dismiss();
+        } else {
+            assert mRequestQueue.contains(delegate);
+            mRequestQueue.remove(delegate);
+        }
+        delegate.destroy();
+    }
+
     private void destroyDelegate() {
         mDialogDelegate.destroy();
         mDialogDelegate = null;