Update the selected file in change view after nav in diff view

+ Share change view state with the diff view to allow changing of
  the selected file index.
+ Remove sessionStorage use case in favor of using change view
  state.
+ Implement [ and ] keyboard shortcuts in change view.

Bug: Issue 3857
Change-Id: Ib6ea751a7e6489012f23727ef69e44923e848704

polygerrit-ui/app/elements/gr-app.html

@@ -99,20 +99,27 @@ limitations under the License.
     </header>
     <main>
       <template is="dom-if" if="{{_showChangeListView}}" restamp="true">
-        <gr-change-list-view params="[[params]]"
+        <gr-change-list-view
+            params="[[params]]"
             view-state="{{_viewState.changeListView}}"
             logged-in="[[_computeLoggedIn(account)]]"></gr-change-list-view>
       </template>
       <template is="dom-if" if="{{_showDashboardView}}" restamp="true">
-        <gr-dashboard-view params="[[params]]"
+        <gr-dashboard-view
+            params="[[params]]"
             view-state="{{_viewState.dashboardView}}"></gr-dashboard-view>
       </template>
       <template is="dom-if" if="{{_showChangeView}}" restamp="true">
-        <gr-change-view server-config="[[config]]"
-            params="[[params]]" view-state="{{_viewState.changeView}}"></gr-change-view>
+        <gr-change-view
+            params="[[params]]"
+            server-config="[[config]]"
+            view-state="{{_viewState.changeView}}"></gr-change-view>
       </template>
       <template is="dom-if" if="{{_showDiffView}}" restamp="true">
-        <gr-diff-view prefs="{{_diffPreferences}}" params="[[params]]"></gr-diff-view>
+        <gr-diff-view
+            params="[[params]]"
+            prefs="{{_diffPreferences}}"
+            change-view-state="{{_viewState.changeView}}"></gr-diff-view>
       </template>
     </main>
     <footer role="contentinfo">
@@ -196,6 +203,7 @@ limitations under the License.
             changeNum: null,
             patchNum: null,
             selectedFileIndex: 0,
+            showReplyDropdown: false,
           },
           changeListView: {
             query: null,

polygerrit-ui/app/elements/gr-change-view.html

@@ -418,9 +418,9 @@ limitations under the License.
           app.accountReady.then(function() {
             if (!this._loggedIn) { return; }
 
-            if (window.sessionStorage.getItem('changeView.showReplyDropdown')) {
+            if (this.viewState.showReplyDropdown) {
               this.$.replyDropdown.open();
-              window.sessionStorage.removeItem('changeView.showReplyDropdown');
+              this.set('viewState.showReplyDropdown', false);
             }
           }.bind(this));
         }.bind(this));

polygerrit-ui/app/elements/gr-diff-view.html

@@ -155,6 +155,11 @@ limitations under the License.
           type: Object,
           value: function() { return document.body; },
         },
+        changeViewState: {
+          type: Object,
+          notify: true,
+          value: function() { return {}; },
+        },
 
         _patchRange: Object,
         _change: Object,
@@ -164,7 +169,10 @@ limitations under the License.
           type: Array,
           value: function() { return []; },
         },
-        _path: String,
+        _path: {
+          type: String,
+          observer: '_pathChanged',
+        },
         _loggedIn: {
           type: Boolean,
           value: false,
@@ -208,9 +216,7 @@ limitations under the License.
           case 65:  // 'a'
             if (!this._loggedIn) { return; }
 
-            // Values can only be strings.
-            window.sessionStorage.setItem(
-                'changeView.showReplyDropdown', 'true');
+            this.set('changeViewState.showReplyDropdown', true);
             // No break here. Allow to fall through.
           case 85:  // 'u'
             if (this._changeNum) {
@@ -266,6 +272,13 @@ limitations under the License.
         this.$.diff.reload();
       },
 
+      _pathChanged: function(path) {
+        if (this._fileList.length == 0) { return; }
+
+        this.set('changeViewState.selectedFileIndex',
+            this._fileList.indexOf(path));
+      },
+
       _computeDiffURL: function(changeNum, patchRange, path) {
         var patchStr = patchRange.patchNum;
         if (patchRange.basePatchNum != null &&

polygerrit-ui/app/elements/gr-file-list.html

@@ -191,15 +191,30 @@ limitations under the License.
             e.preventDefault();
             this.selectedIndex = Math.max(0, this.selectedIndex - 1);
             break;
+          case 219:  // '['
+            e.preventDefault();
+            this._openSelectedFile(this.files.length - 1);
+            break;
+          case 221:  // ']'
+            e.preventDefault();
+            this._openSelectedFile(0);
+            break;
           case 13:  // <enter>
           case 79:  // 'o'
             e.preventDefault();
-            page(this._computeDiffURL(this.changeNum, this.patchNum,
-                this.files[this.selectedIndex].__path));
+            this._openSelectedFile();
             break;
         }
       },
 
+      _openSelectedFile: function(opt_index) {
+        if (opt_index != null) {
+          this.selectedIndex = opt_index;
+        }
+        page(this._computeDiffURL(this.changeNum, this.patchNum,
+            this.files[this.selectedIndex].__path));
+      },
+
       _computeFileSelected: function(index, selectedIndex) {
         return index == selectedIndex;
       },

polygerrit-ui/app/test/gr-diff-view-test.html

@@ -52,6 +52,7 @@ limitations under the License.
       };
       element._fileList = ['chell.go', 'glados.txt', 'wheatley.md'];
       element._path = 'glados.txt';
+      element.changeViewState.selectedFileIndex = 1;
 
       var showStub = sinon.stub(page, 'show');
       MockInteractions.pressAndReleaseKeyOn(element, 85);  // 'u'
@@ -62,20 +63,24 @@ limitations under the License.
       assert(showStub.lastCall.calledWithExactly('/c/42/10/wheatley.md'),
           'Should navigate to /c/42/10/wheatley.md');
       element._path = 'wheatley.md';
+      assert.equal(element.changeViewState.selectedFileIndex, 2);
 
       MockInteractions.pressAndReleaseKeyOn(element, 219);  // '['
       assert(showStub.lastCall.calledWithExactly('/c/42/10/glados.txt'),
           'Should navigate to /c/42/10/glados.txt');
       element._path = 'glados.txt';
+      assert.equal(element.changeViewState.selectedFileIndex, 1);
 
       MockInteractions.pressAndReleaseKeyOn(element, 219);  // '['
       assert(showStub.lastCall.calledWithExactly('/c/42/10/chell.go'),
           'Should navigate to /c/42/10/chell.go');
       element._path = 'chell.go';
+      assert.equal(element.changeViewState.selectedFileIndex, 0);
 
       MockInteractions.pressAndReleaseKeyOn(element, 219);  // '['
       assert(showStub.lastCall.calledWithExactly('/c/42'),
           'Should navigate to /c/42');
+      assert.equal(element.changeViewState.selectedFileIndex, 0);
 
       var showPrefsStub = sinon.stub(element.$.diff, 'showDiffPreferences');
       MockInteractions.pressAndReleaseKeyOn(element, 188);  // ','
@@ -104,9 +109,8 @@ limitations under the License.
 
       element._loggedIn = true;
       MockInteractions.pressAndReleaseKeyOn(element, 65);  // 'a'
-      assert.equal(window.sessionStorage.getItem(
-          'changeView.showReplyDropdown'), 'true');
-      window.sessionStorage.removeItem('changeView.showReplyDropdown');
+      assert.isTrue(element.changeViewState.showReplyDropdown);
+
       assert(showStub.lastCall.calledWithExactly('/c/42'),
           'Should navigate to /c/42');