InlineEdit: Add GET /changes/{id}/edit/{path}/type endpoint

Change-Id: I3b5bb2fab294e5ba560ac2db32dcc80055bdc6a8

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/edit/ChangeEditIT.java

@@ -484,6 +484,18 @@ public class ChangeEditIT extends AbstractDaemonTest {
         .isEqualTo(StringUtils.newStringUtf8(CONTENT_NEW2));
   }
 
+  @Test
+  public void getFileContentTypeRest() throws Exception {
+    Put.Input in = new Put.Input();
+    in.content = RestSession.newRawInput(CONTENT_NEW);
+    assertThat(adminSession.putRaw(urlEditFile(), in.content).getStatusCode())
+        .isEqualTo(SC_NO_CONTENT);
+    RestResponse r = adminSession.get(urlEditFileContentType());
+    assertThat(r.getStatusCode()).isEqualTo(SC_OK);
+    String res = newGson().fromJson(r.getReader(), String.class);
+    assertThat(res).isEqualTo("application/octet-stream");
+  }
+
   @Test
   public void getFileNotFoundRest() throws Exception {
     assertThat(modifier.createEdit(change, ps)).isEqualTo(RefUpdate.Result.NEW);
@@ -606,6 +618,13 @@ public class ChangeEditIT extends AbstractDaemonTest {
         + FILE_NAME;
   }
 
+  private String urlEditFileContentType() {
+    return urlEdit()
+        + "/"
+        + FILE_NAME
+        + "/type";
+  }
+
   private String urlGetFiles() {
     return urlEdit()
         + "?list";