Revert "Split off library classes from server/patch/ into diff/"

This reverts commit 0d157b3561.

Reason for revert: full class name goes into H2 keys and values,
and possibly in other data structures in other deployments
(eg. at google), causing cache misses, warnings and/or more
cache dysfunction.

See also https://bugs.chromium.org/p/gerrit/issues/detail?id=7784&desc=2

Change-Id: I03851b8f783b93929e7dc27548fb75882b6bfe05

java/com/google/gerrit/server/patch/IntraLineDiffKey.java

@@ -0,0 +1,35 @@
+// Copyright (C) 2010 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.patch;
+
+import com.google.auto.value.AutoValue;
+import com.google.gerrit.extensions.client.DiffPreferencesInfo.Whitespace;
+import java.io.Serializable;
+import org.eclipse.jgit.lib.ObjectId;
+
+@AutoValue
+public abstract class IntraLineDiffKey implements Serializable {
+  public static final long serialVersionUID = 8L;
+
+  public static IntraLineDiffKey create(ObjectId aId, ObjectId bId, Whitespace whitespace) {
+    return new AutoValue_IntraLineDiffKey(aId, bId, whitespace);
+  }
+
+  public abstract ObjectId getBlobA();
+
+  public abstract ObjectId getBlobB();
+
+  public abstract Whitespace getWhitespace();
+}