Trying to deflake DiskCacheEntryTest.SimpleCacheCreateRecoverFromRmdir

The test removes |cache_dir_|, which seems risky since other instances might
touch it; so instead put the cache one more level down.

Bug: 999584
Change-Id: I56f100b0308e45f1e6bbc66c7306cbf3af822e99
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1782878Reviewed-by: Eric Orth <ericorth@chromium.org>
Commit-Queue: Maks Orlovich <morlovich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#692946}

net/disk_cache/disk_cache_test_base.cc

@@ -34,7 +34,10 @@ using net::test::IsOk;
 
 DiskCacheTest::DiskCacheTest() {
   CHECK(temp_dir_.CreateUniqueTempDir());
-  cache_path_ = temp_dir_.GetPath();
+  // Put the cache into a subdir of |temp_dir_|, to permit tests to safely
+  // remove the cache directory without risking collisions with other tests.
+  cache_path_ = temp_dir_.GetPath().AppendASCII("cache");
+  CHECK(base::CreateDirectory(cache_path_));
 }
 
 DiskCacheTest::~DiskCacheTest() = default;

net/disk_cache/entry_unittest.cc

@@ -4935,8 +4935,7 @@ TEST_F(DiskCacheEntryTest, SimpleCacheReadCorruptLength) {
   EXPECT_NE(net::OK, OpenEntry(key, &entry));
 }
 
-// TODO(https://crbug.com/999584): Flaky on slower bots.
-TEST_F(DiskCacheEntryTest, DISABLED_SimpleCacheCreateRecoverFromRmdir) {
+TEST_F(DiskCacheEntryTest, SimpleCacheCreateRecoverFromRmdir) {
   // This test runs as APP_CACHE to make operations more synchronous.
   // (in particular we want to see if create succeeded or not, so we don't
   //  want an optimistic one).