[tracing] Sanitize process memory dumps for background mode

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 c18e10c374459182d6fae2cafa22aa5ae80ae9d9..d020c7d652f8f919908fb60ad297757c07249d1a 100644
--- a/base/trace_event/process_memory_dump.h
+++ b/base/trace_event/process_memory_dump.h
@@ -16,6 +16,7 @@
 #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_request_args.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"
@@ -67,7 +68,8 @@ class BASE_EXPORT ProcessMemoryDump {
   static size_t CountResidentBytes(void* start_address, size_t mapped_size);
 #endif
 
-  ProcessMemoryDump(scoped_refptr<MemoryDumpSessionState> session_state);
+  ProcessMemoryDump(scoped_refptr<MemoryDumpSessionState> session_state,
+                    const MemoryDumpArgs& dump_args);
   ~ProcessMemoryDump();
 
   // Creates a new MemoryAllocatorDump with the given name and returns the
@@ -175,10 +177,16 @@ class BASE_EXPORT ProcessMemoryDump {
 
   const HeapDumpsMap& heap_dumps() const { return heap_dumps_; }
 
+  const MemoryDumpArgs& dump_args() const { return dump_args_; }
+
  private:
+  FRIEND_TEST_ALL_PREFIXES(ProcessMemoryDumpTest, BackgroundModeTest);
+
   MemoryAllocatorDump* AddAllocatorDumpInternal(
       std::unique_ptr<MemoryAllocatorDump> mad);
 
+  MemoryAllocatorDump* GetBlackHoleMad();
+
   ProcessMemoryTotals process_totals_;
   bool has_process_totals_;
 
@@ -194,6 +202,18 @@ class BASE_EXPORT ProcessMemoryDump {
   // Keeps track of relationships between MemoryAllocatorDump(s).
   std::vector<MemoryAllocatorDumpEdge> allocator_dumps_edges_;
 
+  // Level of detail of the current dump.
+  const MemoryDumpArgs dump_args_;
+
+  // This allocator dump is returned when an invalid dump is created in
+  // background mode. The attributes of the dump are ignored and not added to
+  // the trace.
+  std::unique_ptr<MemoryAllocatorDump> black_hole_mad_;
+
+  // When set to true, the DCHECK(s) for invalid dump creations on the
+  // background mode are disabled for testing.
+  static bool is_black_hole_non_fatal_for_testing_;
+
   DISALLOW_COPY_AND_ASSIGN(ProcessMemoryDump);
 };