[sql] Track uploads of diagnostic data to prevent duplication.

sql/connection_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/files/memory_mapped_file.h"
 #include "base/files/scoped_file.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
@@ skipping 1369 matching lines @@
 #endif
 
 TEST_F(SQLConnectionTest, OnMemoryDump) {
   base::trace_event::ProcessMemoryDump pmd(nullptr);
   base::trace_event::MemoryDumpArgs args = {
       base::trace_event::MemoryDumpLevelOfDetail::DETAILED};
   ASSERT_TRUE(db().OnMemoryDump(args, &pmd));
   EXPECT_GE(pmd.allocator_dumps().size(), 1u);
 }
 
+TEST_F(SQLConnectionTest, RegisterIntentToUpload) {
+  base::FilePath breadcrumb_path(
+      db_path().DirName().Append(FILE_PATH_LITERAL("sqlite-diag")));
+
+  // No stale diagnostic store.
+  ASSERT_TRUE(!base::PathExists(breadcrumb_path));
+
+  // The histogram tag is required to enable diagnostic features.
+  EXPECT_FALSE(db().RegisterIntentToUpload());
+  EXPECT_TRUE(!base::PathExists(breadcrumb_path));
+
+  db().Close();
+  db().set_histogram_tag("Test");
+  ASSERT_TRUE(db().Open(db_path()));
+
+  // Should signal upload only once.
+  EXPECT_TRUE(db().RegisterIntentToUpload());
+  EXPECT_TRUE(base::PathExists(breadcrumb_path));
+  EXPECT_FALSE(db().RegisterIntentToUpload());
+
+  // Changing the histogram tag should allow new upload to succeed.
+  db().Close();
+  db().set_histogram_tag("NewTest");
+  ASSERT_TRUE(db().Open(db_path()));
+  EXPECT_TRUE(db().RegisterIntentToUpload());
+  EXPECT_FALSE(db().RegisterIntentToUpload());
+
+  // Old tag is still prevented.
+  db().Close();
+  db().set_histogram_tag("Test");
+  ASSERT_TRUE(db().Open(db_path()));
+  EXPECT_FALSE(db().RegisterIntentToUpload());
+}
+
 }  // namespace