Remove adder by clicking once on a different frame

Before this PR, when there was two frames, A and B, if the adder was in
frame A, it was necessary to __double click__ on frame B to remove the
adder and the selection from frame A.

After this PR, __a single click__  on frame B removes the adder and text
selection from frame A. This behaviour is similar to what happens on a
single frame scenario, where a single click removes the adder and the
selection.

src/annotator/guest.js

@@ -15,7 +15,7 @@ import {
 } from './highlighter';
 import { createIntegration } from './integrations';
 import * as rangeUtil from './range-util';
-import { SelectionObserver } from './selection-observer';
+import { SelectionObserver, selectedRange } from './selection-observer';
 import { findClosestOffscreenAnchor } from './util/buckets';
 import { normalizeURI } from './util/url';
 
@@ -303,8 +303,10 @@ export class Guest {
 
   async _connectHost() {
     this._hostRPC.on('clearSelection', () => {
-      this._informHostOnNextSelectionClear = false;
-      removeTextSelection();
+      if (selectedRange(document)) {
+        this._informHostOnNextSelectionClear = false;
+        removeTextSelection();
+      }
     });
 
     this._hostRPC.on('createAnnotation', () => this.createAnnotation());

src/annotator/selection-observer.js

@@ -6,7 +6,7 @@ import { ListenerCollection } from '../shared/listener-collection';
  * @param {Document} document
  * @return {Range|null}
  */
-function selectedRange(document) {
+export function selectedRange(document) {
   const selection = document.getSelection();
   if (!selection || selection.rangeCount === 0) {
     return null;

src/annotator/test/guest-test.js

@@ -43,6 +43,7 @@ describe('Guest', () => {
   let fakePortFinder;
   let FakePortRPC;
   let fakePortRPCs;
+  let fakeSelectedRange;
 
   const createGuest = (config = {}) => {
     const element = document.createElement('div');
@@ -151,6 +152,8 @@ describe('Guest', () => {
       }
     }
 
+    fakeSelectedRange = sinon.stub();
+
     $imports.$mock({
       '../shared/messaging': {
         PortFinder: sinon.stub().returns(fakePortFinder),
@@ -170,6 +173,7 @@ describe('Guest', () => {
       './range-util': rangeUtil,
       './selection-observer': {
         SelectionObserver: FakeSelectionObserver,
+        selectedRange: fakeSelectedRange,
       },
       './util/buckets': {
         findClosestOffscreenAnchor: fakeFindClosestOffscreenAnchor,
@@ -672,26 +676,51 @@ describe('Guest', () => {
       assert.calledWith(hostRPC().call, 'textUnselected');
     });
 
-    it('unselects text if another iframe has made a selection', () => {
-      const removeAllRanges = sandbox.stub();
-      sandbox.stub(document, 'getSelection').returns({ removeAllRanges });
-      const guest = createGuest();
-      guest.selectedRanges = [1];
+    context('on "clearSelection" RPC event', () => {
+      it('if guest has selected text, clears the selection', () => {
+        const removeAllRanges = sandbox.stub();
+        sandbox.stub(document, 'getSelection').returns({ removeAllRanges });
+        const guest = createGuest();
+        guest.selectedRanges = [1];
 
-      simulateSelectionWithText();
-      hostRPC().call.resetHistory();
-      emitHostEvent('clearSelection');
+        // Guest has text selected
+        simulateSelectionWithText();
+        fakeSelectedRange.returns({});
 
-      assert.calledOnce(removeAllRanges);
-      notifySelectionChanged(null); // removing the text selection triggers the selection observer
+        hostRPC().call.resetHistory();
+        emitHostEvent('clearSelection');
 
-      assert.equal(guest.selectedRanges.length, 0);
-      assert.notCalled(hostRPC().call);
+        assert.calledOnce(removeAllRanges);
+        notifySelectionChanged(null); // removing the text selection triggers the selection observer
 
-      // On next selection clear it should be inform the host.
-      notifySelectionChanged(null);
-      assert.calledOnce(hostRPC().call);
-      assert.calledWithExactly(hostRPC().call, 'textUnselected');
+        assert.equal(guest.selectedRanges.length, 0);
+        assert.notCalled(hostRPC().call);
+
+        // On next selection clear it should be inform the host.
+        notifySelectionChanged(null);
+        assert.calledOnce(hostRPC().call);
+        assert.calledWithExactly(hostRPC().call, 'textUnselected');
+      });
+
+      it('if guest has no text selected, does nothing', () => {
+        const removeAllRanges = sandbox.stub();
+        sandbox.stub(document, 'getSelection').returns({ removeAllRanges });
+        const guest = createGuest();
+        guest.selectedRanges = [1];
+
+        // Guest has no text selected
+        fakeSelectedRange.returns(null);
+
+        hostRPC().call.resetHistory();
+        emitHostEvent('clearSelection');
+
+        assert.notCalled(removeAllRanges);
+
+        // On next selection clear it should be inform the host.
+        notifySelectionChanged(null);
+        assert.calledOnce(hostRPC().call);
+        assert.calledWithExactly(hostRPC().call, 'textUnselected');
+      });
     });
   });