Using CodeMirror's lint addon on the UI to display the blame
annotations. It works on both sides of the side-by-side
diff and also supports the auto-merge commit. It requires manual
step to enable the annotations to avoid any unnecessary git
processing and network traffic between the server and client.
Introduces a new dependency on blame-cache in gerrit-server
to reuse BlameCache.
In a following change, the gutter showing the blame info will be
made clickable. Clicking on the gutter will open a new tab that
takes the user to the corresponding change in Gerrit.
The commit SHA-1 hashes are currently not selectable. Making it
so might require an upstream change in CodeMirror's lint addon.
Bug: Issue 1642
Change-Id: I6267d30cbee448f8137e11c7120959dc424eaeeb
b72d4c6d8f