[tracing] Support BACKGROUND mode in MemoryCache dump provider

third_party/WebKit/Source/platform/web_process_memory_dump.h

 // Copyright 2015 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.
 
 #ifndef WebProcessMemoryDump_h
 #define WebProcessMemoryDump_h
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/trace_event/heap_profiler_allocation_context.h"
@@ skipping 21 matching lines @@
 class SkiaTraceMemoryDumpImpl;
 }  // namespace skia
 
 namespace blink {
 
 // Used to specify the type of memory dump the WebProcessMemoryDump should
 // generate on dump requests.
 // TODO(hajimehoshi): Remove this and use base::trace_event::
 // MemoryDumpLevelOfDetail instead.
 enum class WebMemoryDumpLevelOfDetail {
+    Background,
     Light,
     Detailed
 };
 
 // A container which holds all the dumps for the various allocators for a given
 // process. Embedders of WebMemoryDumpProvider are expected to populate a
 // WebProcessMemoryDump instance with the stats of their allocators.
 class PLATFORM_EXPORT WebProcessMemoryDump final {
  public:
   // Creates a standalone WebProcessMemoryDump, which owns the underlying
@@ skipping 108 matching lines @@
 
   // Stores SkTraceMemoryDump for the current ProcessMemoryDump.
   std::vector<std::unique_ptr<skia::SkiaTraceMemoryDumpImpl>> sk_trace_dump_list_;
 
   DISALLOW_COPY_AND_ASSIGN(WebProcessMemoryDump);
 };
 
 }  // namespace blink
 
 #endif  // WebProcessMemoryDump_h