Make URLRequestContext a MemoryDumpProvider (Abandoned)

net/filter/brotli_source_stream.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/filter/brotli_source_stream.h"
 
 #include "base/bind.h"
 #include "base/bit_cast.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/strings/stringprintf.h"
+#include "base/trace_event/memory_allocator_dump.h"
+#include "base/trace_event/process_memory_dump.h"
 #include "net/base/io_buffer.h"
 #include "third_party/brotli/dec/decode.h"
 
 namespace net {
 
 namespace {
 
 const char kBrotli[] = "BROTLI";
 const uint8_t kGzipHeader[] = {0x1f, 0x8b, 0x08};
 
@@ skipping 43 matching lines @@
 
     // All code here is for gathering stats, and can be removed when
     // BrotliSourceStream is considered stable.
     const int kBuckets = 48;
     const int64_t kMaxKb = 1 << (kBuckets / 3);  // 64MiB in KiB
     UMA_HISTOGRAM_CUSTOM_COUNTS("BrotliFilter.UsedMemoryKB",
                                 used_memory_maximum_ / 1024, 1, kMaxKb,
                                 kBuckets);
   }
 
+  void DumpMemoryStatsImpl(
+      base::trace_event::MemoryAllocatorDump* dump) const override {
+    // Log pointer address to avoid duplication though in practice there is
+    // often only one BrotliSourceStream per URLRequest.
+    base::trace_event::MemoryAllocatorDump* brotli_dump =
+        dump->process_memory_dump()->CreateAllocatorDump(base::StringPrintf(
+            "%s/brotli_%p", dump->absolute_name().c_str(), this));

[ssid, 2016/12/02 21:36:35]

Pass the dump name as an extra argument to this function instead of passing
|mad|. You only need the name's prefix here not the dump. This is to make clear
that this function is not changing the |mad| itself, but just using the name to
create different |mad|

+    brotli_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
+                           base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                           used_memory_);
+  }
+
  private:
   // Reported in UMA and must be kept in sync with the histograms.xml file.
   enum class DecodingStatus : int {
     DECODING_IN_PROGRESS = 0,
     DECODING_DONE,
     DECODING_ERROR,
 
     DECODING_STATUS_COUNT
     // DECODING_STATUS_COUNT must always be the last element in this enum.
   };
@@ skipping 107 matching lines @@
 };
 
 }  // namespace
 
 std::unique_ptr<FilterSourceStream> CreateBrotliSourceStream(
     std::unique_ptr<SourceStream> previous) {
   return base::WrapUnique(new BrotliSourceStream(std::move(previous)));
 }
 
 }  // namespace net