Add Remote Tracking Branch to the diff summary area

Summary: For the case that `remote_tracking_branch` of that specific diff is not empty, and is also not `master`; we would display that on the diff summary.

Reviewed By: evangrayk

Differential Revision: D62051002

fbshipit-source-id: 9a0b03230c33ede41365c2c9ca970af792d5817f

addons/isl/src/CommitInfoView/CommitInfoView.tsx

@@ -248,6 +248,12 @@ export function CommitInfoDetails({commit}: {commit: CommitInfo}) {
     previousFieldsBeingEdited,
   );
 
+  const diffSummaries = useAtomValue(allDiffSummaries);
+  const remoteTrackingBranch = provider?.getRemoteTrackingBranch(
+    diffSummaries?.value ?? null,
+    commit.diffId ?? null,
+  );
+
   const isSplitSuggestionSupported = provider?.isSplitSuggestionSupported() ?? false;
   const selectedFiles = uncommittedChanges.filter(f =>
     selection.isFullyOrPartiallySelected(f.path),
@@ -344,6 +350,17 @@ export function CommitInfoDetails({commit}: {commit: CommitInfo}) {
               />
             );
           })}
+        {remoteTrackingBranch !== null ? (
+          <Section>
+            <SmallCapsTitle>
+              <Icon icon="source-control"></Icon>
+              <T>Remote Tracking Branch</T>
+            </SmallCapsTitle>
+            <div className="commit-info-tokenized-field">
+              <span className="token">{remoteTrackingBranch}</span>
+            </div>
+          </Section>
+        ) : null}
         <Divider />
         {commit.isDot && !isAmendDisabled ? (
           <Section data-testid="changes-to-amend">

addons/isl/src/codeReview/UICodeReviewProvider.ts

@@ -50,6 +50,13 @@ export interface UICodeReviewProvider {
 
   RepoInfo(): JSX.Element | null;
 
+  getRemoteTrackingBranch(
+    allDiffSummaries: Map<string, DiffSummary> | null,
+    diffId: DiffId | null,
+  ): string | null;
+
+  getRemoteTrackingBranchFromDiffSummary(diff: DiffSummary | undefined | null): string | null;
+
   isDiffClosed(summary: DiffSummary): boolean;
 
   isDiffEligibleForCleanup(summary: DiffSummary): boolean;

addons/isl/src/codeReview/github/github.tsx

@@ -86,6 +86,15 @@ export class GithubUICodeReviewProvider implements UICodeReviewProvider {
       </span>
     );
   };
+
+  getRemoteTrackingBranch(): string | null {
+    return null;
+  }
+
+  getRemoteTrackingBranchFromDiffSummary(): string | null {
+    return null;
+  }
+
   isSplitSuggestionSupported(): boolean {
     return false;
   }