Add support for light dumps in SkTraceMemoryDump interface.

tests/TraceMemoryDumpTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkTraceMemoryDump.h"
 
 #include "Test.h"
 
 /*
  * Build test for SkTraceMemoryDump.
  */
 class TestSkTraceMemoryDump : public SkTraceMemoryDump {
 public:
     TestSkTraceMemoryDump() { }
     ~TestSkTraceMemoryDump() override { }
 
     void dumpNumericValue(const char* dumpName, const char* valueName, const char* units,
                           uint64_t value) override { }
     void setMemoryBacking(const char* dumpName, const char* backingType,
                           const char* backingObjectId) override { }
     void setDiscardableMemoryBacking(
         const char* dumpName,
         const SkDiscardableMemory& discardableMemoryObject) override { }
+    LevelOfDetail getRequestedDetails() const override {
+        return SkTraceMemoryDump::kObjectsBreakdowns_LevelOfDetail;
+    }
 };
 
 DEF_TEST(SkTraceMemoryDump, reporter) {
     TestSkTraceMemoryDump x;
     x.dumpNumericValue("foobar", "size", "bytes", 42);
+    if (x.getRequestedDetails() == SkTraceMemoryDump::kObjectsBreakdowns_LevelOfDetail) {
+        x.dumpNumericValue("foobar/object1", "size", "bytes", 23);
+    }
 }