In AutoValue, replace uses of Set<TypeMirror> with a custom TypeMirrorSet. TypeMirror instances don't always compare equal even when they refer to the same type, so using Set<TypeMirror> can produce anomalous results.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=69698186
Get auto-value to use auto-common
Merge pull request #113 from google/moe_writing_branch_from_7120492f2aebecbb56ccf44fe7fbf3fc57622004

In AutoValue, replace uses of Set<TypeMirror> with a custom TypeMirrorSet