memory-infra: Start disentangling tracing from memory-infra

base/trace_event/memory_dump_manager.h

Index: base/trace_event/memory_dump_manager.h
diff --git a/base/trace_event/memory_dump_manager.h b/base/trace_event/memory_dump_manager.h
index 4e5f8a2f77d00afae4d3cffc59678a19421071e5..fde2fffb8f3d1f9bb50bd292ae6fc0b1334b7e58 100644
--- a/base/trace_event/memory_dump_manager.h
+++ b/base/trace_event/memory_dump_manager.h
@@ -46,7 +46,7 @@ class MemoryDumpSessionState;
 // This is the interface exposed to the rest of the codebase to deal with
 // memory tracing. The main entry point for clients is represented by
 // RequestDumpPoint(). The extension by Un(RegisterDumpProvider).
-class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
+class BASE_EXPORT MemoryDumpManager {
  public:
   static const char* const kTraceCategory;
   static const char* const kLogPrefix;
@@ -119,9 +119,9 @@ class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
   void RequestGlobalDump(MemoryDumpType dump_type,
                          MemoryDumpLevelOfDetail level_of_detail);
 
-  // TraceLog::EnabledStateObserver implementation.
-  void OnTraceLogEnabled() override;
-  void OnTraceLogDisabled() override;
+  // XXX
+  virtual void Enable();

[Primiano Tucci (use gerrit), 2017/04/13 15:22:37]

out of cusiority, why virtual?

[hjd, 2017/04/13 16:32:18]

So we can mock it in the frontend tests.

[hjd, 2017/04/19 09:54:56]

If we don't want to test this for now I will undo this, but I'll do it last
after we agreed on everything else so I can keep a branch around with all the
changes we need to re-add the tests in case we want them.

+  virtual void Disable();
 
   // Enable heap profiling if kEnableHeapProfiling is specified.
   void EnableHeapProfilingIfNeeded();
@@ -167,6 +167,8 @@ class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
   friend struct DefaultSingletonTraits<MemoryDumpManager>;
   friend class MemoryDumpManagerDelegate;
   friend class MemoryDumpManagerTest;
+  friend class MemoryTracingFrontendTest;
+  friend class MockMemoryDumpManager;
   friend class memory_instrumentation::MemoryDumpManagerDelegateImplTest;
 
   // Holds the state of a process memory dump that needs to be carried over
@@ -230,7 +232,7 @@ class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
   static const char* const kSystemAllocatorPoolName;
 
   MemoryDumpManager();
-  ~MemoryDumpManager() override;
+  virtual ~MemoryDumpManager();
 
   static void SetInstanceForTesting(MemoryDumpManager* instance);
   static uint32_t GetDumpsSumKb(const std::string&, const ProcessMemoryDump*);