Use provided revWalk ObjectReader to read changed content.

The plugin was using repo.open instead of revWalk.getObjectReader().
This meant that objects being newly added to the repo would not be
able to be referenced, causing an error.

Change-Id: Id6dbc36a22dc3ca464647bff02b731dd9fb27020
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidator.java
index add3731..4a0751f 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/BlockedKeywordValidator.java
@@ -162,7 +162,7 @@
     checkCommitMessageForBlockedKeywords(blockedKeywordPartterns, messages, c.getFullMessage());
     Map<String, ObjectId> content = CommitUtils.getChangedContent(repo, c, revWalk);
     for (String path : content.keySet()) {
-      ObjectLoader ol = repo.open(content.get(path));
+      ObjectLoader ol = revWalk.getObjectReader().open(content.get(path));
       try (InputStream in = ol.openStream()) {
         if (RawText.isBinary(in) || contentTypeUtil.isBlacklistedBinaryContentType(ol, path, cfg)) {
           continue;
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidator.java
index 281ec44..3303fa9 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/ContentTypeValidator.java
@@ -155,7 +155,7 @@
     List<CommitValidationMessage> messages = new LinkedList<>();
     Map<String, ObjectId> content = CommitUtils.getChangedContent(repo, c, revWalk);
     for (String path : content.keySet()) {
-      ObjectLoader ol = repo.open(content.get(path));
+      ObjectLoader ol = revWalk.getObjectReader().open(content.get(path));
       String contentType = contentTypeUtil.getContentType(ol, path);
       if ((contentTypeUtil.matchesAny(contentType, blockedTypes) && !whitelist)
           || (!contentTypeUtil.matchesAny(contentType, blockedTypes) && whitelist)) {
diff --git a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidator.java b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidator.java
index 7f5d79f..f0b8931 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/uploadvalidator/InvalidLineEndingValidator.java
@@ -134,7 +134,7 @@
     List<CommitValidationMessage> messages = new LinkedList<>();
     Map<String, ObjectId> content = CommitUtils.getChangedContent(repo, c, revWalk);
     for (String path : content.keySet()) {
-      ObjectLoader ol = repo.open(content.get(path));
+      ObjectLoader ol = revWalk.getObjectReader().open(content.get(path));
       try (InputStream in = ol.openStream()) {
         if (RawText.isBinary(in) || contentTypeUtil.isBlacklistedBinaryContentType(ol, path, cfg)) {
           continue;