Update diff line hash via Gerrit.Nav

Formerly, the gr-diff-view generated and updated the URL hash that
indicates the location of the diff cursor, regardless of the hash
generation scheme implemented in _generateUrl. With this change, the
diff view uses the _generateUrl for the cursor-location-specific URL.

Change-Id: Ia70a298f114c9eae9cdc5b0a8f73d7ecab55896e

polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.js

@@ -226,13 +226,14 @@
     },
 
     /**
-     * Get a short address for the location of the cursor. Such as '123' for
-     * line 123 of the revision, or 'b321' for line 321 of the base patch.
-     * Returns an empty string if an address is not available.
-     * @return {string}
+     * Get an object describing the location of the cursor. Such as
+     * {leftSide: false, number: 123} for line 123 of the revision, or
+     * {leftSide: true, number: 321} for line 321 of the base patch.
+     * Returns null if an address is not available.
+     * @return {?Object}
      */
     getAddress() {
-      if (!this.diffRow) { return ''; }
+      if (!this.diffRow) { return null; }
 
       // Get the line-number cell targeted by the cursor. If the mode is unified
       // then prefer the revision cell if available.
@@ -245,12 +246,15 @@
       } else {
         cell = this.diffRow.querySelector('.lineNum.' + this.side);
       }
-      if (!cell) { return ''; }
+      if (!cell) { return null; }
 
       const number = cell.getAttribute('data-value');
-      if (!number || number === 'FILE') { return ''; }
+      if (!number || number === 'FILE') { return null; }
 
-      return (cell.matches('.left') ? 'b' : '') + number;
+      return {
+        leftSide: cell.matches('.left'),
+        number: parseInt(number, 10),
+      };
     },
 
     _getViewMode() {

polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html

@@ -240,27 +240,31 @@ limitations under the License.
 
     test('getAddress', () => {
       // It should initialize to the first chunk: line 5 of the revision.
-      assert.equal(cursorElement.getAddress(), '5');
+      assert.deepEqual(cursorElement.getAddress(),
+          {leftSide: false, number: 5});
 
       // Revision line 4 is up.
       cursorElement.moveUp();
-      assert.equal(cursorElement.getAddress(), '4');
+      assert.deepEqual(cursorElement.getAddress(),
+          {leftSide: false, number: 4});
 
       // Base line 4 is left.
       cursorElement.moveLeft();
-      assert.equal(cursorElement.getAddress(), 'b4');
+      assert.deepEqual(cursorElement.getAddress(), {leftSide: true, number: 4});
 
       // Moving to the next chunk takes it back to the start.
       cursorElement.moveToNextChunk();
-      assert.equal(cursorElement.getAddress(), '5');
+      assert.deepEqual(cursorElement.getAddress(),
+          {leftSide: false, number: 5});
 
       // The following chunk is a removal starting on line 10 of the base.
       cursorElement.moveToNextChunk();
-      assert.equal(cursorElement.getAddress(), 'b10');
+      assert.deepEqual(cursorElement.getAddress(),
+          {leftSide: true, number: 10});
 
-      // Should be an empty string if there is no selection.
+      // Should be null if there is no selection.
       cursorElement.$.cursorManager.unsetCursor();
-      assert.equal(cursorElement.getAddress(), '');
+      assert.isNotOk(cursorElement.getAddress());
     });
 
     test('_findRowByNumberAndFile', () => {

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

@@ -727,7 +727,13 @@
 
     _onLineSelected(e, detail) {
       this.$.cursor.moveToLineNumber(detail.number, detail.side);
-      history.replaceState(null, '', '#' + this.$.cursor.getAddress());
+      if (!this._change) { return; }
+      const cursorAddress = this.$.cursor.getAddress();
+      const url = Gerrit.Nav.getUrlForDiffById(this._changeNum,
+          this._change.project, this._path, this._patchRange.patchNum,
+          this._patchRange.basePatchNum, cursorAddress.number,
+          cursorAddress.leftSide);
+      history.replaceState(null, '', url);
     },
 
     _computeDownloadLink(changeNum, patchRange, path) {

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

@@ -620,9 +620,18 @@ limitations under the License.
     });
 
     test('_onLineSelected', () => {
+      const getUrlStub = sandbox.stub(Gerrit.Nav, 'getUrlForDiffById');
       const replaceStateStub = sandbox.stub(history, 'replaceState');
       const moveStub = sandbox.stub(element.$.cursor, 'moveToLineNumber');
+      sandbox.stub(element.$.cursor, 'getAddress')
+          .returns({number: 123, isLeftSide: false});
 
+      element._changeNum = 321;
+      element._change = {_number: 321, project: 'foo/bar'};
+      element._patchRange = {
+        basePatchNum: '3',
+        patchNum: '5',
+      };
       const e = {};
       const detail = {number: 123, side: 'right'};
 
@@ -633,6 +642,7 @@ limitations under the License.
       assert.equal(moveStub.lastCall.args[1], detail.side);
 
       assert.isTrue(replaceStateStub.called);
+      assert.isTrue(getUrlStub.called);
     });
 
     test('_getDiffViewMode', () => {