leveldb: Added leveldb_chrome::CorruptClosedDBForTesting.

There are several tests that need to corrupt a leveldb database
which is fairly tightly coupled to the leveldb implementation.
Adding CorruptClosedDBForTesting to centralize this functionality.

Bug: None
Change-Id: Ia875afe50ad61e8e91264d0145efdcc734665507
Reviewed-on: https://chromium-review.googlesource.com/710740
Reviewed-by: Jian Li <[email protected]>
Reviewed-by: Sky Malice <[email protected]>
Reviewed-by: Tommy Nyquist <[email protected]>
Commit-Queue: Chris Mumford <[email protected]>
Cr-Commit-Position: refs/heads/master@{#511289}
diff --git a/components/gcm_driver/DEPS b/components/gcm_driver/DEPS
index 911879a4..99d1592 100644
--- a/components/gcm_driver/DEPS
+++ b/components/gcm_driver/DEPS
@@ -14,4 +14,5 @@
   "+google_apis/gcm",
   "+jni",
   "+net",
+  "+third_party/leveldatabase",  # Only used for tests.
 ]