Add support for light dumps in SkTraceMemoryDump interface.

tests/TraceMemoryDumpTest.cpp

Index: tests/TraceMemoryDumpTest.cpp
diff --git a/tests/TraceMemoryDumpTest.cpp b/tests/TraceMemoryDumpTest.cpp
index cda007631838bc8a267023ef72138dc7d67108d8..f28eedae1b74688ad79a6f6b2f0cf0282c06fcce 100644
--- a/tests/TraceMemoryDumpTest.cpp
+++ b/tests/TraceMemoryDumpTest.cpp
@@ -24,9 +24,15 @@ public:
     void setDiscardableMemoryBacking(
         const char* dumpName,
         const SkDiscardableMemory& discardableMemoryObject) override { }
+    LevelOfDetails getRequestedDetails() const override {
+        return SkTraceMemoryDump::kDetailedDump;
+    }
 };
 
 DEF_TEST(SkTraceMemoryDump, reporter) {
     TestSkTraceMemoryDump x;
     x.dumpNumericValue("foobar", "size", "bytes", 42);
+    if (x.getRequestedDetails() & SkTraceMemoryDump::kDetailedDump) {
+        x.dumpNumericValue("foobar/object1", "size", "bytes", 23);
+    }
 }