Remove non-functional `window-scroll` Angular directive

The /stream view is supposed to automatically fetch new annotations as
you scroll. However this has been broken for a very long time. The
code responsible for making this happen relied on `scroll` events on the `window`.
However the stream content has for a long time been contained in a scrollable
`.app-content-wrapper` container, so no such events were emitted.

For the moment, just remove the non-functional code as that gets us a
step closer to completing the migration away from Angular.

src/sidebar/components/stream-content.js

@@ -62,8 +62,6 @@ function StreamContentController(
 
   // Sort the stream so that the newest annotations are at the top
   store.setSortKey('Newest');
-
-  this.loadMore = fetch;
 }
 
 export default {

src/sidebar/directive/test/window-scroll-test.js

-import angular from 'angular';
-
-const inject = angular.mock.inject;
-
-import windowScroll from '../window-scroll';
-
-describe('windowScroll', function() {
-  let directive = null;
-
-  let doc = null;
-  let html = null;
-  let view = null;
-
-  let scope = null;
-  let elem = null;
-  let attr = null;
-
-  beforeEach(inject(function($injector) {
-    directive = $injector.invoke(windowScroll);
-
-    html = {};
-    view = {
-      addEventListener: sinon.spy(),
-      removeEventListener: sinon.spy(),
-    };
-
-    doc = { documentElement: html, defaultView: view };
-
-    scope = { $apply: sinon.stub().yields(), $on: sinon.stub() };
-    elem = {
-      prop: sinon
-        .stub()
-        .withArgs('ownerDocument')
-        .returns(doc),
-    };
-    attr = { windowScroll: sinon.stub() };
-
-    directive.link(scope, elem, attr);
-  }));
-
-  it('installs a scroll handler on the window', function() {
-    assert.calledOnce(view.addEventListener);
-    assert.calledWith(view.addEventListener, 'scroll', sinon.match.func);
-
-    assert.calledOnce(scope.$on);
-    assert.calledWith(scope.$on, '$destroy', sinon.match.func);
-
-    scope.$on.firstCall.args[1]();
-
-    const handler = view.addEventListener.firstCall.args[1];
-    assert.calledOnce(view.removeEventListener);
-    assert.calledWith(view.removeEventListener, 'scroll', handler);
-  });
-
-  describe('attribute argument', function() {
-    let callback = null;
-    let handler = null;
-
-    beforeEach(function() {
-      callback = attr.windowScroll;
-      handler = view.addEventListener.firstCall.args[1];
-      html.clientHeight = 100;
-      html.scrollHeight = 1000;
-      view.scrollY = 0;
-    });
-
-    it('is not called when scrolling near the top of the view', function() {
-      handler();
-      assert.notCalled(callback);
-    });
-
-    it('is not called when scrolling near the middle of the view', function() {
-      handler();
-      view.scrollY = 500;
-
-      handler();
-      assert.notCalled(callback);
-    });
-
-    it('is called when one screen remains', function() {
-      handler();
-
-      view.scrollY = 800;
-      handler();
-
-      assert.calledOnce(callback);
-    });
-
-    describe('throttle', function() {
-      it('prevents extraneous calls', function() {
-        view.scrollY = 800;
-        handler();
-        handler();
-        assert.calledOnce(callback);
-      });
-
-      it('allows calls after the view grows', function() {
-        view.scrollY = 800;
-        handler();
-        assert.calledOnce(callback);
-
-        html.scrollHeight = 2000;
-        handler();
-        assert.calledOnce(callback);
-
-        view.scrollY = 1800;
-        handler();
-        assert.calledTwice(callback);
-      });
-    });
-  });
-});

src/sidebar/directive/window-scroll.js

-export default function windowScrollDirective() {
-  return {
-    link: function(scope, elem, attr) {
-      let active = true;
-      const html = elem.prop('ownerDocument').documentElement;
-      const view = elem.prop('ownerDocument').defaultView;
-
-      function onScroll() {
-        const clientHeight = html.clientHeight;
-        const scrollHeight = html.scrollHeight;
-        if (view.scrollY + clientHeight >= scrollHeight - clientHeight) {
-          if (active) {
-            active = false;
-            scope.$apply(attr.windowScroll);
-          }
-        } else {
-          active = true;
-        }
-      }
-
-      view.addEventListener('scroll', onScroll, false);
-
-      scope.$on('$destroy', function() {
-        view.removeEventListener('scroll', onScroll);
-      });
-    },
-  };
-}

src/sidebar/index.js

@@ -160,10 +160,6 @@ import sidebarContent from './components/sidebar-content';
 import streamContent from './components/stream-content';
 import threadList from './components/thread-list';
 
-// Angular directives.
-
-import windowScrollDirective from './directive/window-scroll';
-
 // Services.
 
 import bridgeService from '../shared/bridge';
@@ -293,7 +289,6 @@ function startAngularApp(config) {
     .component('tagList', wrapComponent(TagList))
     .component('threadList', threadList)
     .component('topBar', wrapComponent(TopBar))
-    .directive('windowScroll', windowScrollDirective)
 
     // Register services, the store and utilities with Angular, so that
     // Angular components can use them.

src/sidebar/templates/stream-content.html

-<span window-scroll="vm.loadMore(20)">
-  <thread-list
-    on-change-collapsed="vm.setCollapsed(id, collapsed)"
-    show-document-info="true"
-    thread="vm.rootThread()">
-  </thread-list>
-</span>
+<thread-list
+  on-change-collapsed="vm.setCollapsed(id, collapsed)"
+  show-document-info="true"
+  thread="vm.rootThread()">
+</thread-list>