ahat: add support for diffing two heap dumps.

ahat now has the option to specify a --baseline hprof file to use as
the basis for comparing two heap dumps. When a baseline hprof file is
provided, ahat will highlight how the heap dump has changed relative
to the hprof file.

Differences that are highlighted include:
* overall heap sizes
* total bytes and number of allocations by type
* new and deleted instances of a given type
* retained sizes of objects
* instance fields, static fields, and array elements of modified objects

Also:
* Remove support for showing NativeAllocations, because I haven't ever
  found it to be useful, it is not obvious what a "native" allocation
  is, and I don't feel like adding diff support for them.
* Remove help page. Because it is outdated, not well maintained, and
  not very helpful in the first place.

Test: m ahat-test
Test: Run in diff mode for tests and added new tests for diff.
Test: Manually run with and without diff mode on heap dumps from system server.
Bug: 33770653
Change-Id: Id9a392ac75588200e716bbc3edbae6e9cd97c26b

1 files changed, 0 insertions, 47 deletions

diff --git a/tools/ahat/test/NativeAllocationTest.java b/tools/ahat/test/NativeAllocationTest.java
deleted file mode 100644
index 9babab903e..0000000000
--- a/tools/ahat/test/NativeAllocationTest.java
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * Copyright (C) 2016 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.android.ahat;
-
-import com.android.ahat.heapdump.AhatInstance;
-import com.android.ahat.heapdump.AhatSnapshot;
-import com.android.ahat.heapdump.NativeAllocation;
-import java.io.IOException;
-import org.junit.Test;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.fail;
-
-public class NativeAllocationTest {
-
-  @Test
-  public void nativeAllocation() throws IOException {
-    TestDump dump = TestDump.getTestDump();
-
-    AhatSnapshot snapshot = dump.getAhatSnapshot();
-    AhatInstance referent = dump.getDumpedAhatInstance("anObject");
-    for (NativeAllocation alloc : snapshot.getNativeAllocations()) {
-      if (alloc.referent.equals(referent)) {
-        assertEquals(42 , alloc.size);
-        assertEquals(referent.getHeap(), alloc.heap);
-        assertEquals(0xABCDABCD , alloc.pointer);
-        return;
-      }
-    }
-    fail("No native allocation found with anObject as the referent");
-  }
-}
-