Update from https://crrev.com/333737

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 889356d65aa57d8599a715ab4cdb5ad062d2aa82..88ce28abe245a7ec2f8f58ebaffe3f39999611bb 100644
--- a/base/trace_event/process_memory_dump.h
+++ b/base/trace_event/process_memory_dump.h
@@ -5,12 +5,15 @@
 #ifndef BASE_TRACE_EVENT_PROCESS_MEMORY_DUMP_H_
 #define BASE_TRACE_EVENT_PROCESS_MEMORY_DUMP_H_
 
+#include <vector>
+
 #include "base/base_export.h"
 #include "base/containers/hash_tables.h"
 #include "base/containers/small_map.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_vector.h"
 #include "base/trace_event/memory_allocator_dump.h"
+#include "base/trace_event/memory_allocator_dump_guid.h"
 #include "base/trace_event/memory_dump_session_state.h"
 #include "base/trace_event/process_memory_maps.h"
 #include "base/trace_event/process_memory_totals.h"
@@ -30,6 +33,13 @@ class MemoryDumpSessionState;
 // dump point time.
 class BASE_EXPORT ProcessMemoryDump {
  public:
+  struct MemoryAllocatorDumpEdge {
+    MemoryAllocatorDumpGuid source;
+    MemoryAllocatorDumpGuid target;
+    int importance;
+    const char* type;
+  };
+
   // Maps allocator dumps absolute names (allocator_name/heap/subheap) to
   // MemoryAllocatorDump instances.
   using AllocatorDumpsMap =
@@ -41,6 +51,18 @@ class BASE_EXPORT ProcessMemoryDump {
   // Called at trace generation time to populate the TracedValue.
   void AsValueInto(TracedValue* value) const;
 
+  // Removes all the MemoryAllocatorDump(s) contained in this instance. This
+  // ProcessMemoryDump can be safely reused as if it was new once this returns.
+  void Clear();
+
+  // Merges all MemoryAllocatorDump(s) contained in |other| inside this
+  // ProcessMemoryDump, transferring their ownership to this instance.
+  // |other| will be an empty ProcessMemoryDump after this method returns.
+  // This is to allow dump providers to pre-populate ProcessMemoryDump instances
+  // and later move their contents into the ProcessMemoryDump passed as argument
+  // of the MemoryDumpProvider::OnMemoryDump(ProcessMemoryDump*) callback.
+  void TakeAllDumpsFrom(ProcessMemoryDump* other);
+
   ProcessMemoryTotals* process_totals() { return &process_totals_; }
   bool has_process_totals() const { return has_process_totals_; }
   void set_has_process_totals() { has_process_totals_ = true; }
@@ -56,21 +78,62 @@ class BASE_EXPORT ProcessMemoryDump {
   //       by this provider. It is possible to specify nesting by using a
   //       path-like string (e.g., v8/isolate1/heap1, v8/isolate1/heap2).
   //       Leading or trailing slashes are not allowed.
+  //   guid: an optional identifier, unique among all processes within the
+  //       scope of a global dump. This is only relevant when using
+  //       AddOwnershipEdge(). If omitted, it will be automatically generated.
   // ProcessMemoryDump handles the memory ownership of its MemoryAllocatorDumps.
   MemoryAllocatorDump* CreateAllocatorDump(const std::string& absolute_name);
+  MemoryAllocatorDump* CreateAllocatorDump(const std::string& absolute_name,
+                                           const MemoryAllocatorDumpGuid& guid);
 
   // Looks up a MemoryAllocatorDump given its allocator and heap names, or
   // nullptr if not found.
   MemoryAllocatorDump* GetAllocatorDump(const std::string& absolute_name) const;
 
+  // Creates a shared MemoryAllocatorDump, to express cross-process sharing.
+  // Shared allocator dumps are allowed to have duplicate guids within the
+  // global scope, in order to reference the same dump from multiple processes.
+  // See the design doc goo.gl/keU6Bf for reference usage patterns.
+  MemoryAllocatorDump* CreateSharedGlobalAllocatorDump(
+      const MemoryAllocatorDumpGuid& guid);
+
+  // Looks up a shared MemoryAllocatorDump given its guid.
+  MemoryAllocatorDump* GetSharedGlobalAllocatorDump(
+      const MemoryAllocatorDumpGuid& guid) const;
+
   // Returns the map of the MemoryAllocatorDumps added to this dump.
   const AllocatorDumpsMap& allocator_dumps() const { return allocator_dumps_; }
 
+  // Adds an ownership relationship between two MemoryAllocatorDump(s) with the
+  // semantics: |source| owns |target|, and has the effect of attributing
+  // the memory usage of |target| to |source|. |importance| is optional and
+  // relevant only for the cases of co-ownership, where it acts as a z-index:
+  // the owner with the highest importance will be attributed |target|'s memory.
+  void AddOwnershipEdge(const MemoryAllocatorDumpGuid& source,
+                        const MemoryAllocatorDumpGuid& target,
+                        int importance);
+  void AddOwnershipEdge(const MemoryAllocatorDumpGuid& source,
+                        const MemoryAllocatorDumpGuid& target);
+
+  const std::vector<MemoryAllocatorDumpEdge>& allocator_dumps_edges() const {
+    return allocator_dumps_edges_;
+  }
+
+  // Utility method to add a suballocation relationship with the following
+  // semantics: |source| is suballocated from |target_node_name|.
+  // This creates a child node of |target_node_name| and adds an ownership edge
+  // between |source| and the new child node. As a result, the UI will not
+  // account the memory of |source| in the target node.
+  void AddSuballocation(const MemoryAllocatorDumpGuid& source,
+                        const std::string& target_node_name);
+
   const scoped_refptr<MemoryDumpSessionState>& session_state() const {
     return session_state_;
   }
 
  private:
+  void AddAllocatorDumpInternal(MemoryAllocatorDump* mad);
+
   ProcessMemoryTotals process_totals_;
   bool has_process_totals_;
 
@@ -85,6 +148,9 @@ class BASE_EXPORT ProcessMemoryDump {
   // State shared among all PMDs instances created in a given trace session.
   scoped_refptr<MemoryDumpSessionState> session_state_;
 
+  // Keeps track of relationships between MemoryAllocatorDump(s).
+  std::vector<MemoryAllocatorDumpEdge> allocator_dumps_edges_;
+
   DISALLOW_COPY_AND_ASSIGN(ProcessMemoryDump);
 };