Set display line on inline diffs

The gr-diff-view has a set of rules that determine whether the
horizontal line under the target row is visible. Extend these rules to
the gr-file-list for inline diffs.

Bug: Issue 6308
Change-Id: I23a8a0612f045e87e4940bb06988cf215cdd6990

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

@@ -323,6 +323,7 @@ limitations under the License.
             if="[[_isFileExpanded(file.__path, _expandedFilePaths.*)]]">
           <gr-diff
               no-auto-render
+              display-line="[[_displayLine]]"
               inline-index=[[index]]
               hidden="[[!_isFileExpanded(file.__path, _expandedFilePaths.*)]]"
               change-num="[[changeNum]]"

polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js

@@ -110,6 +110,7 @@
         type: Array,
         value() { return []; },
       },
+      _displayLine: Boolean,
     },
 
     behaviors: [
@@ -138,6 +139,7 @@
       'n': '_handleNKey',
       'p': '_handlePKey',
       'shift+a': '_handleCapitalAKey',
+      'esc': '_handleEscKey',
     },
 
     reload() {
@@ -482,6 +484,7 @@
       e.preventDefault();
       if (this._showInlineDiffs) {
         this.$.diffCursor.moveDown();
+        this._displayLine = true;
       } else {
         this.$.fileCursor.next();
         this.selectedIndex = this.$.fileCursor.index;
@@ -496,6 +499,7 @@
       e.preventDefault();
       if (this._showInlineDiffs) {
         this.$.diffCursor.moveUp();
+        this._displayLine = true;
       } else {
         this.$.fileCursor.previous();
         this.selectedIndex = this.$.fileCursor.index;
@@ -895,5 +899,12 @@
         }
       }
     },
+
+    _handleEscKey(e) {
+      if (this.shouldSuppressKeyboardShortcut(e) ||
+          this.modifierPressed(e)) { return; }
+      e.preventDefault();
+      this._displayLine = false;
+    },
   });
 })();

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

@@ -1222,5 +1222,24 @@ limitations under the License.
       element._openSelectedFile();
       assert.isTrue(showStub.called);
     });
+
+    test('_displayLine', () => {
+      sandbox.stub(element, 'shouldSuppressKeyboardShortcut', () => false);
+      sandbox.stub(element, 'modifierPressed', () => false);
+      element._showInlineDiffs = true;
+      const mockEvent = {preventDefault() {}};
+
+      element._displayLine = false;
+      element._handleDownKey(mockEvent);
+      assert.isTrue(element._displayLine);
+
+      element._displayLine = false;
+      element._handleUpKey(mockEvent);
+      assert.isTrue(element._displayLine);
+
+      element._displayLine = true;
+      element._handleEscKey(mockEvent);
+      assert.isFalse(element._displayLine);
+    });
   });
 </script>