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 Because it is outdated, not well maintained, and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, 52 deletions

diff --git a/tools/ahat/src/HelpHandler.java b/tools/ahat/src/HelpHandler.java
deleted file mode 100644
index 8de3c85f5c..0000000000
--- a/tools/ahat/src/HelpHandler.java
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * Copyright (C) 2015 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.google.common.io.ByteStreams;
-import com.sun.net.httpserver.HttpExchange;
-import com.sun.net.httpserver.HttpHandler;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.PrintStream;
-
-/**
- * HelpHandler.
- *
- * HttpHandler to show the help page.
- */
-class HelpHandler implements HttpHandler {
-
-  @Override
-  public void handle(HttpExchange exchange) throws IOException {
-    ClassLoader loader = HelpHandler.class.getClassLoader();
-    exchange.getResponseHeaders().add("Content-Type", "text/html;charset=utf-8");
-    exchange.sendResponseHeaders(200, 0);
-    PrintStream ps = new PrintStream(exchange.getResponseBody());
-    HtmlDoc doc = new HtmlDoc(ps, DocString.text("ahat"), DocString.uri("style.css"));
-    doc.menu(Menu.getMenu());
-
-    InputStream is = loader.getResourceAsStream("help.html");
-    if (is == null) {
-      ps.println("No help available.");
-    } else {
-      ByteStreams.copy(is, ps);
-    }
-
-    doc.close();
-    ps.close();
-  }
-}