Fix crash in InvokeOnMemoryDump when tracing

components/tracing/common/process_metrics_memory_dump_provider_unittest.cc

Index: components/tracing/common/process_metrics_memory_dump_provider_unittest.cc
diff --git a/components/tracing/common/process_metrics_memory_dump_provider_unittest.cc b/components/tracing/common/process_metrics_memory_dump_provider_unittest.cc
index 95a565d148ab8b502af840f0339672c10eb4d3c8..f257527c6b5c87ec42b26d7a74630ed8d78d5bbe 100644
--- a/components/tracing/common/process_metrics_memory_dump_provider_unittest.cc
+++ b/components/tracing/common/process_metrics_memory_dump_provider_unittest.cc
@@ -11,10 +11,12 @@
 #include "base/files/file_util.h"
 #include "base/memory/ptr_util.h"
 #include "base/process/process_metrics.h"
+#include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/process_memory_dump.h"
 #include "base/trace_event/process_memory_maps.h"
 #include "base/trace_event/process_memory_totals.h"
 #include "base/trace_event/trace_event_argument.h"
+#include "testing/gmock/include/gmock/gmock.h"

[Primiano Tucci (use gerrit), 2017/03/15 12:44:40]

I think this is a leftover, right? you are not using gmock anymore (I think)

[hjd, 2017/03/15 14:23:12]

Done.

 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(OS_MACOSX)
@@ -393,4 +395,52 @@ TEST(ProcessMetricsMemoryDumpProviderTest, NoDuplicateRegions) {
 
 #endif  // defined(OS_MACOSX)
 
+class MockMemoryDumpProvider : public ProcessMetricsMemoryDumpProvider {
+ public:
+  MOCK_METHOD2(OnMemoryDump,

[Primiano Tucci (use gerrit), 2017/03/15 12:44:40]

are you really using this mocked method? I think this is a leftover of the
previous attempt right?

[hjd, 2017/03/15 14:23:12]

Done.

+               bool(const base::trace_event::MemoryDumpArgs& args,
+                    base::trace_event::ProcessMemoryDump* pmd));
+
+  MockMemoryDumpProvider(base::ProcessId process);
+  ~MockMemoryDumpProvider() override;
+};
+
+std::unordered_set<MockMemoryDumpProvider*> live_mocks;

[Primiano Tucci (use gerrit), 2017/03/15 12:44:40]

nit: g_ -> g_live_mocks (same with dead) as these are globals

[hjd, 2017/03/15 14:23:12]

Done.

+std::unordered_set<MockMemoryDumpProvider*> dead_mocks;
+
+MockMemoryDumpProvider::MockMemoryDumpProvider(base::ProcessId process)
+    : ProcessMetricsMemoryDumpProvider(process) {
+  live_mocks.insert(this);
+}
+
+MockMemoryDumpProvider::~MockMemoryDumpProvider() {
+  //    ASSERT_TRUE(live_mocks.find(this) != live_mocks.end());
+  live_mocks.erase(this);
+  dead_mocks.insert(this);
+}
+
+TEST(ProcessMetricsMemoryDumpProviderTest, DoubleRegister) {
+  auto factory = [](base::ProcessId process) {
+    return std::unique_ptr<ProcessMetricsMemoryDumpProvider>(
+        new MockMemoryDumpProvider(process));
+  };
+  ProcessMetricsMemoryDumpProvider::factory_for_testing = factory;
+  ProcessMetricsMemoryDumpProvider::RegisterForProcess(1);
+  ProcessMetricsMemoryDumpProvider::RegisterForProcess(1);
+  EXPECT_EQ(1u, live_mocks.size());

[Primiano Tucci (use gerrit), 2017/03/15 12:44:40]

I'd make this an ASSERT_EQ and remove the if(...==1) below

[hjd, 2017/03/15 14:23:12]

Done.

+  EXPECT_EQ(1u, dead_mocks.size());
+  auto* manager = base::trace_event::MemoryDumpManager::GetInstance();
+  if (live_mocks.size() == 1u) {
+    MockMemoryDumpProvider* live_mock = *live_mocks.begin();
+    EXPECT_TRUE(manager->IsDumpProviderRegisteredForTesting(live_mock));
+  }
+  if (dead_mocks.size() == 1u) {
+    auto* dead_mock = *dead_mocks.begin();
+    EXPECT_FALSE(manager->IsDumpProviderRegisteredForTesting(dead_mock));
+  }
+  ProcessMetricsMemoryDumpProvider::UnregisterForProcess(1);
+  live_mocks.clear();
+  dead_mocks.clear();
+}
+
 }  // namespace tracing