Use store selectors instead of `getState` in `FrameSyncService`

Remove the last remaining usage of `store.getState()` outside of the
store implementation in favor of the `store.allAnnotations()` selector
method.

This allows simplifying the state structure in the fake store that the
`FrameSyncService` tests create.

src/sidebar/services/frame-sync.js

@@ -66,7 +66,7 @@ export class FrameSyncService {
 
       watch(
         store.subscribe,
-        [() => store.getState().annotations.annotations, () => store.frames()],
+        [() => store.allAnnotations(), () => store.frames()],
         ([annotations, frames], [prevAnnotations]) => {
           let publicAnns = 0;
           const inSidebar = new Set();

src/sidebar/services/test/frame-sync-test.js

@@ -54,8 +54,11 @@ describe('FrameSyncService', () => {
 
   beforeEach(function () {
     fakeStore = createFakeStore(
-      { annotations: { annotations: [] } },
+      { annotations: [] },
       {
+        allAnnotations() {
+          return this.getState().annotations;
+        },
         connectFrame: sinon.stub(),
         destroyFrame: sinon.stub(),
         findIDsForTags: sinon.stub(),
@@ -110,7 +113,7 @@ describe('FrameSyncService', () => {
   context('when annotations are loaded into the sidebar', function () {
     it('sends a "loadAnnotations" message to the frame', function () {
       fakeStore.setState({
-        annotations: { annotations: [fixtures.ann] },
+        annotations: [fixtures.ann],
       });
       assert.calledWithMatch(
         fakeBridge.call,
@@ -122,12 +125,12 @@ describe('FrameSyncService', () => {
     it('sends a "loadAnnotations" message only for new annotations', function () {
       const ann2 = Object.assign({}, fixtures.ann, { $tag: 't2', id: 'a2' });
       fakeStore.setState({
-        annotations: { annotations: [fixtures.ann] },
+        annotations: [fixtures.ann],
       });
       fakeBridge.call.reset();
 
       fakeStore.setState({
-        annotations: { annotations: [fixtures.ann, ann2] },
+        annotations: [fixtures.ann, ann2],
       });
 
       assert.calledWithMatch(
@@ -139,7 +142,7 @@ describe('FrameSyncService', () => {
 
     it('does not send a "loadAnnotations" message for replies', function () {
       fakeStore.setState({
-        annotations: { annotations: [annotationFixtures.newReply()] },
+        annotations: [annotationFixtures.newReply()],
       });
       assert.isFalse(fakeBridge.call.calledWith('loadAnnotations'));
     });
@@ -148,7 +151,7 @@ describe('FrameSyncService', () => {
   context('when annotation count has changed', function () {
     it('sends a "publicAnnotationCountChanged" message to the frame when there are public annotations', function () {
       fakeStore.setState({
-        annotations: { annotations: [annotationFixtures.publicAnnotation()] },
+        annotations: [annotationFixtures.publicAnnotation()],
       });
       assert.calledWithMatch(
         fakeBridge.call,
@@ -162,7 +165,7 @@ describe('FrameSyncService', () => {
       delete annot.permissions;
 
       fakeStore.setState({
-        annotations: { annotations: [annot] },
+        annotations: [annot],
       });
       assert.calledWithMatch(
         fakeBridge.call,
@@ -174,7 +177,7 @@ describe('FrameSyncService', () => {
     it('does not send a "publicAnnotationCountChanged" message to the frame if annotation fetch is not complete', function () {
       fakeStore.frames.returns([{ uri: 'http://example.com' }]);
       fakeStore.setState({
-        annotations: { annotations: [annotationFixtures.publicAnnotation()] },
+        annotations: [annotationFixtures.publicAnnotation()],
       });
       assert.isFalse(
         fakeBridge.call.calledWith('publicAnnotationCountChanged')
@@ -184,7 +187,7 @@ describe('FrameSyncService', () => {
     it('does not send a "publicAnnotationCountChanged" message if there are no connected frames', function () {
       fakeStore.frames.returns([]);
       fakeStore.setState({
-        annotations: { annotations: [annotationFixtures.publicAnnotation()] },
+        annotations: [annotationFixtures.publicAnnotation()],
       });
       assert.isFalse(
         fakeBridge.call.calledWith('publicAnnotationCountChanged')
@@ -195,10 +198,10 @@ describe('FrameSyncService', () => {
   context('when annotations are removed from the sidebar', function () {
     it('sends a "deleteAnnotation" message to the frame', function () {
       fakeStore.setState({
-        annotations: { annotations: [fixtures.ann] },
+        annotations: [fixtures.ann],
       });
       fakeStore.setState({
-        annotations: { annotations: [] },
+        annotations: [],
       });
       assert.calledWithMatch(
         fakeBridge.call,