[memory-infra] Add method to override importance of ownership edges

base/trace_event/process_memory_dump.h

Index: base/trace_event/process_memory_dump.h
diff --git a/base/trace_event/process_memory_dump.h b/base/trace_event/process_memory_dump.h
index 45a973964231fa7d794b2be72d3175871970720b..83ef2eb837610d5ed1c091798df9f3403a9cc295 100644
--- a/base/trace_event/process_memory_dump.h
+++ b/base/trace_event/process_memory_dump.h
@@ -39,10 +39,10 @@ class TracedValue;
 class BASE_EXPORT ProcessMemoryDump {
  public:
   struct MemoryAllocatorDumpEdge {
-    MemoryAllocatorDumpGuid source;
     MemoryAllocatorDumpGuid target;
     int importance;
     const char* type;
+    bool overridable;
   };
 
   // Maps allocator dumps absolute names (allocator_name/heap/subheap) to
@@ -53,6 +53,9 @@ class BASE_EXPORT ProcessMemoryDump {
   using HeapDumpsMap =
       std::unordered_map<std::string, std::unique_ptr<TracedValue>>;
 
+  using AllocatorDumpEdgesMap =
+      std::unordered_map<MemoryAllocatorDumpGuid, MemoryAllocatorDumpEdge>;

[hajimehoshi, 2017/05/31 05:45:51]

Just std::map might be better (See /base/containers/README.md).

BTW, what would happen if there are two or more edges from one source to
different targets?

[ssid, 2017/06/02 23:14:46]

Done
This is not supported. A dump cannot own 2 dumps.

+
 #if defined(COUNT_RESIDENT_BYTES_SUPPORTED)
   // Returns the number of bytes in a kernel memory page. Some platforms may
   // have a different value for kernel page sizes from user page sizes. It is
@@ -135,7 +138,14 @@ class BASE_EXPORT ProcessMemoryDump {
   void AddOwnershipEdge(const MemoryAllocatorDumpGuid& source,
                         const MemoryAllocatorDumpGuid& target);
 
-  const std::vector<MemoryAllocatorDumpEdge>& allocator_dumps_edges() const {
+  void CreateSharedMemoryOwnershipEdge(
+      const MemoryAllocatorDumpGuid& client_dump_guid,
+      const MemoryAllocatorDumpGuid& client_global_dump_guid,
+      bool is_weak,
+      int importance,
+      uint64_t shm_unguessable_token);
+
+  const AllocatorDumpEdgesMap& allocator_dumps_edges_for_testing() const {
     return allocator_dumps_edges_;
   }
 
@@ -181,12 +191,17 @@ class BASE_EXPORT ProcessMemoryDump {
 
  private:
   FRIEND_TEST_ALL_PREFIXES(ProcessMemoryDumpTest, BackgroundModeTest);
+  FRIEND_TEST_ALL_PREFIXES(ProcessMemoryDumpTest, OverrideOwnershipEdge);
 
   MemoryAllocatorDump* AddAllocatorDumpInternal(
       std::unique_ptr<MemoryAllocatorDump> mad);
 
   MemoryAllocatorDump* GetBlackHoleMad();
 
+  void AddOverridableOwnershipEdge(const MemoryAllocatorDumpGuid& source,
+                                   const MemoryAllocatorDumpGuid& target,
+                                   int importance);
+
   ProcessMemoryTotals process_totals_;
   bool has_process_totals_;
 
@@ -200,7 +215,7 @@ class BASE_EXPORT ProcessMemoryDump {
   scoped_refptr<MemoryDumpSessionState> session_state_;
 
   // Keeps track of relationships between MemoryAllocatorDump(s).
-  std::vector<MemoryAllocatorDumpEdge> allocator_dumps_edges_;
+  AllocatorDumpEdgesMap allocator_dumps_edges_;
 
   // Level of detail of the current dump.
   const MemoryDumpArgs dump_args_;