[Extensions] Re-enable some ImageWriterWriteFromUrlOperationTest

tests.

The SelectTargetWithoutExtension and SelectTargetWithExtension
tests were disabled on TSAN configurations because they flaky.
I ran these tests for 3000 iterations on TSAN bots without any
failures.

Bug: 859317
Change-Id: Ie8031f79b8725229d7dc5294855ef89730084d85
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2199996
Commit-Queue: Karan Bhatia <karandeepb@chromium.org>
Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#769066}

chrome/browser/extensions/api/image_writer_private/write_from_url_operation_unittest.cc

@@ -137,15 +137,7 @@ class ImageWriterWriteFromUrlOperationTest : public ImageWriterUnitTestBase {
   MockOperationManager manager_;
 };
 
-// Crashes on Tsan.  http://crbug.com/859317
-#if defined(THREAD_SANITIZER)
-#define MAYBE_SelectTargetWithoutExtension DISABLED_SelectTargetWithoutExtension
-#define MAYBE_SelectTargetWithExtension DISABLED_SelectTargetWithExtension
-#else
-#define MAYBE_SelectTargetWithoutExtension SelectTargetWithoutExtension
-#define MAYBE_SelectTargetWithExtension SelectTargetWithExtension
-#endif
-TEST_F(ImageWriterWriteFromUrlOperationTest, MAYBE_SelectTargetWithoutExtension) {
+TEST_F(ImageWriterWriteFromUrlOperationTest, SelectTargetWithoutExtension) {
   scoped_refptr<WriteFromUrlOperationForTest> operation =
       CreateOperation(GURL("http://localhost/foo/bar"), "");
 
@@ -160,7 +152,7 @@ TEST_F(ImageWriterWriteFromUrlOperationTest, MAYBE_SelectTargetWithoutExtension)
   content::RunAllTasksUntilIdle();
 }
 
-TEST_F(ImageWriterWriteFromUrlOperationTest, MAYBE_SelectTargetWithExtension) {
+TEST_F(ImageWriterWriteFromUrlOperationTest, SelectTargetWithExtension) {
   scoped_refptr<WriteFromUrlOperationForTest> operation =
       CreateOperation(GURL("http://localhost/foo/bar.zip"), "");
 
@@ -173,9 +165,6 @@ TEST_F(ImageWriterWriteFromUrlOperationTest, MAYBE_SelectTargetWithExtension) {
 
   operation->Cancel();
 }
-#undef MAYBE_SelectTargetWithoutExtension
-#undef MAYBE_SelectTargetWithExtension
-
 
 TEST_F(ImageWriterWriteFromUrlOperationTest, DownloadFile) {
   // This test actually triggers the URL fetch code, which will drain the