[tracing] Memory dump provider for leveldb_proto

components/leveldb_proto/leveldb_database.h

Index: components/leveldb_proto/leveldb_database.h
diff --git a/components/leveldb_proto/leveldb_database.h b/components/leveldb_proto/leveldb_database.h
index a3caf2f932ae6ee16217bbca2bc016858c08d82d..4474a87ca644160a20e404eb200cf18900aaa25c 100644
--- a/components/leveldb_proto/leveldb_database.h
+++ b/components/leveldb_proto/leveldb_database.h
@@ -13,6 +13,7 @@
 #include "base/macros.h"
 #include "base/strings/string_split.h"
 #include "base/threading/thread_collision_warner.h"
+#include "base/trace_event/memory_dump_provider.h"
 
 namespace base {
 class HistogramBase;
@@ -29,14 +30,14 @@ namespace leveldb_proto {
 // Interacts with the LevelDB third party module.
 // Once constructed, function calls and destruction should all occur on the
 // same thread (not necessarily the same as the constructor).
-class LevelDB {
+class LevelDB : base::trace_event::MemoryDumpProvider {
  public:
   // Constructor. Does *not* open a leveldb - only initialize this class.
   // |client_name| is the name of the "client" that owns this instance. Used
   // for UMA statics as so: LevelDB.<value>.<client name>. It is best to not
   // change once shipped.
   explicit LevelDB(const char* client_name);
-  virtual ~LevelDB();
+  ~LevelDB() override;
 
   virtual bool InitWithOptions(const base::FilePath& database_dir,
                                const leveldb::Options& options);
@@ -48,6 +49,10 @@ class LevelDB {
 
   static bool Destroy(const base::FilePath& database_dir);
 
+  // base::trace_event::MemoryDumpProvider implementation.
+  bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& dump_args,
+                    base::trace_event::ProcessMemoryDump* pmd) override;
+
  private:
   DFAKE_MUTEX(thread_checker_);
 
@@ -56,6 +61,8 @@ class LevelDB {
   std::unique_ptr<leveldb::Env> env_;
   std::unique_ptr<leveldb::DB> db_;
   base::HistogramBase* open_histogram_;
+  // Name of the client shown in chrome://tracing.
+  std::string client_name_;
 
   DISALLOW_COPY_AND_ASSIGN(LevelDB);
 };