Ignore unexpected single-column entry in uploads.log

There are two kind of formats used in the crash logging file.
- [CSV format] the old version to deprecate.
- [JSON format] the new version with better extensibility.

To decide the format of a specific log entry. We should make sure it is
not only a JSON type, but also a JSON dictionary type. Otherwise the
invalid CSV entry with single column will be wrongly treated as JSON
format, then enter the parsing logic. It may cause unexpected crash.

Bug: 1142529
Change-Id: I899940eece378b0359188dc14d617fb0570dedfa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2538216Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Anqing Zhao <anqing@chromium.org>
Cr-Commit-Position: refs/heads/master@{#829305}

components/upload_list/text_log_upload_list.cc

@@ -240,7 +240,7 @@ void TextLogUploadList::ParseLogEntries(
     std::unique_ptr<UploadInfo> info = nullptr;
     base::Optional<base::Value> json = base::JSONReader::Read(line);
 
-    if (json.has_value())
+    if (json.has_value() && json->is_dict())
       info = TryParseJsonLogEntry(json.value());
     else
       info = TryParseCsvLogEntry(line);

components/upload_list/text_log_upload_list_unittest.cc

@@ -596,6 +596,34 @@ TEST_F(TextLogUploadListTest, SkipInvalidEntry_JSON) {
   EXPECT_EQ(1u, uploads.size());
 }
 
+// Test log entry string with only single column.
+// Such kind of lines are considered as invalid CSV entry. They should be
+// skipped in parsing the log file.
+TEST_F(TextLogUploadListTest, SkipBlankOrCorruptedEntry) {
+  std::string test_entry;
+
+  // Add an empty line.
+  test_entry += "\n";
+
+  // Add a line with only single column.
+  test_entry.append(kTestUploadTime);
+  test_entry += "\n";
+
+  WriteUploadLog(test_entry);
+
+  scoped_refptr<TextLogUploadList> upload_list =
+      new TextLogUploadList(log_path());
+
+  base::RunLoop run_loop;
+  upload_list->Load(run_loop.QuitClosure());
+  run_loop.Run();
+
+  std::vector<UploadList::UploadInfo> uploads;
+  upload_list->GetUploads(999, &uploads);
+
+  EXPECT_EQ(0u, uploads.size());
+}
+
 TEST_F(TextLogUploadListTest, ClearUsingUploadTime) {
   constexpr time_t kTestTime = 1234u;
   constexpr char kOtherEntry[] = "4567,def\n";