https://cs.chromium.org/chromium/src/third_party/WebKit/LayoutTests/storage/indexeddb has too many tests. That directory should only contain tests that aren't feasible in web-platform-tests (WPT).

We should go through each test in the directory and do one of the following.

(1) If the test could not be done in WPT, add document the reason in an HTML comment towards the top of the file.
(2) If the test is redundant with a WPT test, delete it. The CL description should point to the WPT test that provides redundant coverage.
(3) If none of the above apply, move the test to WPT.

As an example, the following test can definitely be expressed in WPT:
https://cs.chromium.org/chromium/src/third_party/WebKit/LayoutTests/storage/indexeddb/blob-contenttype.html

This is a pretty good introduction to Blink for an interested person with previous Web development experience.