Add support for light dumps in SkTraceMemoryDump interface.

src/core/SkResourceCache.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkChecksum.h"
 #include "SkMessageBus.h"
 #include "SkMipMap.h"
@@ skipping 657 matching lines @@
     SkDebugf("RC: %12s bytes %9lu  discardable %p\n",
              rec.getCategory(), rec.bytesUsed(), rec.diagnostic_only_getDiscardable());
 }
 
 void SkResourceCache::TestDumpMemoryStatistics() {
     VisitAll(dump_visitor, nullptr);
 }
 
 static void sk_trace_dump_visitor(const SkResourceCache::Rec& rec, void* context) {
     SkTraceMemoryDump* dump = static_cast<SkTraceMemoryDump*>(context);
-    SkString dump_name = SkStringPrintf("skia/sk_resource_cache/%s_%p", rec.getCategory(), &rec);
+    SkString dumpName = SkStringPrintf("skia/sk_resource_cache/%s_%p", rec.getCategory(), &rec);
     SkDiscardableMemory* discardable = rec.diagnostic_only_getDiscardable();
     if (discardable) {
-        dump->setDiscardableMemoryBacking(dump_name.c_str(), *discardable);
+        dump->setDiscardableMemoryBacking(dumpName.c_str(), *discardable);
     } else {
-        dump->dumpNumericValue(dump_name.c_str(), "size", "bytes", rec.bytesUsed());
-        dump->setMemoryBacking(dump_name.c_str(), "malloc", nullptr);
+        dump->dumpNumericValue(dumpName.c_str(), "size", "bytes", rec.bytesUsed());
+        dump->setMemoryBacking(dumpName.c_str(), "malloc", nullptr);
     }
 }
 
 void SkResourceCache::DumpMemoryStatistics(SkTraceMemoryDump* dump) {
+    // Since resource could be backed by malloc or discardable, the cache always dumps detailed
+    // stats to be accurate.
     VisitAll(sk_trace_dump_visitor, dump);
 }