diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.js
index a9242be..d2731a2 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.js
@@ -20,9 +20,9 @@
   // Prevent redefinition.
   if (window.GrDiffBuilderBinary) { return; }
 
-  function GrDiffBuilderBinary(diff, patchRange, commentThreadEls, prefs,
+  function GrDiffBuilderBinary(diff, commentThreadEls, prefs,
       outputEl) {
-    GrDiffBuilder.call(this, diff, patchRange, commentThreadEls, prefs,
+    GrDiffBuilder.call(this, diff, commentThreadEls, prefs,
         outputEl);
   }
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.js
index c52a504..f05f4f0 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.js
@@ -22,9 +22,9 @@
 
   const IMAGE_MIME_PATTERN = /^image\/(bmp|gif|jpeg|jpg|png|tiff|webp)$/;
 
-  function GrDiffBuilderImage(diff, patchRange, commentThreadEls, prefs,
+  function GrDiffBuilderImage(diff, commentThreadEls, prefs,
       outputEl, baseImage, revisionImage) {
-    GrDiffBuilderSideBySide.call(this, diff, patchRange, commentThreadEls,
+    GrDiffBuilderSideBySide.call(this, diff, commentThreadEls,
         prefs, outputEl, []);
     this._baseImage = baseImage;
     this._revisionImage = revisionImage;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.js
index da085c2..81cbabb 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.js
@@ -20,9 +20,9 @@
   // Prevent redefinition.
   if (window.GrDiffBuilderSideBySide) { return; }
 
-  function GrDiffBuilderSideBySide(diff, patchRange, commentThreadEls,
+  function GrDiffBuilderSideBySide(diff, commentThreadEls,
       prefs, outputEl, layers) {
-    GrDiffBuilder.call(this, diff, patchRange, commentThreadEls, prefs,
+    GrDiffBuilder.call(this, diff, commentThreadEls, prefs,
         outputEl, layers);
   }
   GrDiffBuilderSideBySide.prototype = Object.create(GrDiffBuilder.prototype);
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.js
index 0657ee4..2dcdee4 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.js
@@ -20,9 +20,9 @@
   // Prevent redefinition.
   if (window.GrDiffBuilderUnified) { return; }
 
-  function GrDiffBuilderUnified(diff, patchRange, commentThreadEls, prefs,
+  function GrDiffBuilderUnified(diff, commentThreadEls, prefs,
       outputEl, layers) {
-    GrDiffBuilder.call(this, diff, patchRange, commentThreadEls, prefs,
+    GrDiffBuilder.call(this, diff, commentThreadEls, prefs,
         outputEl, layers);
   }
   GrDiffBuilderUnified.prototype = Object.create(GrDiffBuilder.prototype);
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html
index e77eb57..420a14f 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html
@@ -169,8 +169,7 @@
           // Stop the processor and syntax layer (if they're running).
           this.cancel();
 
-          this._builder = this._getDiffBuilder(
-              this.diff, comments.meta.patchRange, prefs);
+          this._builder = this._getDiffBuilder(this.diff, prefs);
 
           this.$.processor.context = prefs.context;
           this.$.processor.keyLocations = this._getKeyLocations(comments,
@@ -294,7 +293,7 @@
           throw Error(`Invalid preference value: ${pref}`);
         },
 
-        _getDiffBuilder(diff, patchRange, prefs) {
+        _getDiffBuilder(diff, prefs) {
           if (isNaN(prefs.tab_size) || prefs.tab_size <= 0) {
             this._handlePreferenceError('tab size');
             return;
@@ -307,19 +306,19 @@
 
           let builder = null;
           if (this.isImageDiff) {
-            builder = new GrDiffBuilderImage(diff, patchRange,
+            builder = new GrDiffBuilderImage(diff,
               this._commentThreadElements, prefs, this.diffElement,
               this.baseImage, this.revisionImage);
           } else if (diff.binary) {
             // If the diff is binary, but not an image.
-            return new GrDiffBuilderBinary(diff, patchRange,
+            return new GrDiffBuilderBinary(diff,
                 this._commentThreadElements, prefs, this.diffElement);
           } else if (this.viewMode === DiffViewMode.SIDE_BY_SIDE) {
-            builder = new GrDiffBuilderSideBySide(diff, patchRange,
+            builder = new GrDiffBuilderSideBySide(diff,
                 this._commentThreadElements, prefs, this.diffElement,
                 this._layers);
           } else if (this.viewMode === DiffViewMode.UNIFIED) {
-            builder = new GrDiffBuilderUnified(diff, patchRange,
+            builder = new GrDiffBuilderUnified(diff,
                 this._commentThreadElements, prefs, this.diffElement,
                 this._layers);
           }
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js
index 6ea48ac..d428f68 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js
@@ -96,10 +96,9 @@
    */
   const REGEX_TAB_OR_SURROGATE_PAIR = /\t|[\uD800-\uDBFF][\uDC00-\uDFFF]/;
 
-  function GrDiffBuilder(diff, patchRange, commentThreadEls, prefs,
+  function GrDiffBuilder(diff, commentThreadEls, prefs,
       outputEl, layers) {
     this._diff = diff;
-    this._patchRange = patchRange;
     this._prefs = prefs;
     this._outputEl = outputEl;
     this.groups = [];
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html
index c277f34..fd74d55 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html
@@ -75,8 +75,7 @@
         show_tabs: true,
         tab_size: 4,
       };
-      builder = new GrDiffBuilder(
-          {content: []}, {left: [], right: []}, [], prefs);
+      builder = new GrDiffBuilder({content: []}, [], prefs);
     });
 
     teardown(() => { sandbox.restore(); });
@@ -329,9 +328,7 @@
       r5.setAttribute('comment-side', 'right');
       r5.setAttribute('line-num', 5);
 
-      builder = new GrDiffBuilder(
-          {content: []}, {basePatchNum: 'PARENT', patchNum: '3'}, [l3, l5, r5],
-          prefs);
+      builder = new GrDiffBuilder({content: []}, [l3, l5, r5], prefs);
 
       function checkThreadGroupProps(threadGroupEl,
           expectedThreadEls) {
@@ -357,8 +354,6 @@
           builder._commentThreadGroupForLine(line, GrDiffBuilder.Side.LEFT);
       checkThreadGroupProps(threadGroupEl, [l5]);
 
-      builder._patchRange.basePatchNum = '1';
-
       threadGroupEl = builder._commentThreadGroupForLine(line);
       checkThreadGroupProps(threadGroupEl, [l5, r5]);
 
@@ -370,8 +365,6 @@
           builder._commentThreadGroupForLine(line, GrDiffBuilder.Side.RIGHT);
       checkThreadGroupProps(threadGroupEl, [r5]);
 
-      builder._patchRange.basePatchNum = 'PARENT';
-
       line = new GrDiffLine(GrDiffLine.Type.REMOVE);
       line.beforeNumber = 5;
       line.afterNumber = 5;
@@ -389,7 +382,7 @@
     test('_handlePreferenceError called with invalid preference', () => {
       sandbox.stub(element, '_handlePreferenceError');
       const prefs = {tab_size: 0};
-      element._getDiffBuilder(element.diff, undefined, prefs);
+      element._getDiffBuilder(element.diff, prefs);
       assert.isTrue(element._handlePreferenceError.lastCall
           .calledWithExactly('tab size'));
     });
@@ -947,8 +940,7 @@
         outputEl = element.queryEffectiveChildren('#diffTable');
         comments = {left: [], right: [], meta: {patchRange: undefined}};
         sandbox.stub(element, '_getDiffBuilder', () => {
-          const builder = new GrDiffBuilder(
-              {content}, undefined, [], prefs, outputEl);
+          const builder = new GrDiffBuilder({content}, [], prefs, outputEl);
           sandbox.stub(builder, 'addColumns');
           builder.buildSectionElement = function(group) {
             const section = document.createElement('stub');
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
index 4befd2f..62284ad 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
@@ -302,8 +302,7 @@
 
         const mock = document.createElement('mock-diff-response');
         element.$.diffBuilder._builder = element.$.diffBuilder._getDiffBuilder(
-            mock.diffResponse, {left: [], right: []},
-            {tab_size: 2, line_length: 80});
+            mock.diffResponse, {tab_size: 2, line_length: 80});
 
         // No thread groups.
         assert.isNotOk(element._getThreadGroupForLine(contentEl));