Minor fixes to Mojo MemoryDumpProvider.

mojo/edk/system/handle_table.cc

 // Copyright 2014 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.
 
 #include "mojo/edk/system/handle_table.h"
 
 #include <stdint.h>
 
 #include <limits>
 
@@ skipping 14 matching lines @@
       return "data_pipe_producer";
     case Dispatcher::Type::DATA_PIPE_CONSUMER:
       return "data_pipe_consumer";
     case Dispatcher::Type::SHARED_BUFFER:
       return "shared_buffer";
     case Dispatcher::Type::WATCHER:
       return "watcher";
     case Dispatcher::Type::PLATFORM_HANDLE:
       return "platform_handle";
   }
+  NOTREACHED();
   return "unknown";
 }
 
-const char* kDumpProviderName = "MojoHandleTable";
-
 }  // namespace
 
 HandleTable::HandleTable() {
-  base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
-      this, kDumpProviderName, nullptr);
 }
 
 HandleTable::~HandleTable() {
-  base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
-      this, kDumpProviderName, nullptr);
 }
 
 base::Lock& HandleTable::GetLock() {
   return lock_;
 }
 
 MojoHandle HandleTable::AddDispatcher(scoped_refptr<Dispatcher> dispatcher) {
   // Oops, we're out of handles.
   if (next_available_handle_ == MOJO_HANDLE_INVALID)
     return MOJO_HANDLE_INVALID;
@@ skipping 104 matching lines @@
 bool HandleTable::OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
                                base::trace_event::ProcessMemoryDump* pmd) {
   // Create entries for all relevant dispatcher types to ensure they are present
   // in the final dump.
   std::map<Dispatcher::Type, int> handle_count;
   handle_count[Dispatcher::Type::MESSAGE_PIPE];
   handle_count[Dispatcher::Type::DATA_PIPE_PRODUCER];
   handle_count[Dispatcher::Type::DATA_PIPE_CONSUMER];
   handle_count[Dispatcher::Type::SHARED_BUFFER];
   handle_count[Dispatcher::Type::WATCHER];
   handle_count[Dispatcher::Type::PLATFORM_HANDLE];

[ssid, 2017/06/08 18:12:36]

Are these lines required? The last time I tested just the statement below works
fine.

[erikchen, 2017/06/09 00:18:12]

As I commented above, this causes the entries to be created in the map, which
causes us to emit "0" for entries that otherwise would be omitted entirely.

[ssid, 2017/06/09 00:38:28]

Acknowledged.

 
   // Count the number of each dispatcher type.
   {
     base::AutoLock lock(GetLock());
     for (const auto& entry : handles_) {
       ++handle_count[entry.second.dispatcher->GetType()];
     }
   }
 
   base::trace_event::MemoryAllocatorDump* outer_dump =
@@ skipping 11 matching lines @@
 
 HandleTable::Entry::Entry(scoped_refptr<Dispatcher> dispatcher)
     : dispatcher(std::move(dispatcher)) {}
 
 HandleTable::Entry::Entry(const Entry& other) = default;
 
 HandleTable::Entry::~Entry() {}
 
 }  // namespace edk
 }  // namespace mojo