[tracing] Use EstimateMemoryUsage() in deduplicators.

Both type name and stack deduplicators need to estimate their memory
overhead. Previously they were using simplistic models and estimated
only half of their actual memory usage. This CL changes estimation
methods to use EstimateMemoryUsage(), resulting in better accuracy.

Review-Url: https://codereview.chromium.org/2514913002
Cr-Commit-Position: refs/heads/master@{#434728}

base/trace_event/heap_profiler_stack_frame_deduplicator.cc

@@ -11,6 +11,7 @@
 #include <utility>
 
 #include "base/strings/stringprintf.h"
+#include "base/trace_event/memory_usage_estimator.h"
 #include "base/trace_event/trace_event_argument.h"
 #include "base/trace_event/trace_event_memory_overhead.h"
 
@@ -23,6 +24,10 @@ StackFrameDeduplicator::FrameNode::FrameNode(StackFrame frame,
 StackFrameDeduplicator::FrameNode::FrameNode(const FrameNode& other) = default;
 StackFrameDeduplicator::FrameNode::~FrameNode() {}
 
+size_t StackFrameDeduplicator::FrameNode::EstimateMemoryUsage() const {
+  return base::trace_event::EstimateMemoryUsage(children);
+}
+
 StackFrameDeduplicator::StackFrameDeduplicator() {}
 StackFrameDeduplicator::~StackFrameDeduplicator() {}
 
@@ -116,19 +121,10 @@ void StackFrameDeduplicator::AppendAsTraceFormat(std::string* out) const {
 
 void StackFrameDeduplicator::EstimateTraceMemoryOverhead(
     TraceEventMemoryOverhead* overhead) {
-  // The sizes here are only estimates; they fail to take into account the
-  // overhead of the tree nodes for the map, but as an estimate this should be
-  // fine.
-  size_t maps_size = roots_.size() * sizeof(std::pair<StackFrame, int>);
-  size_t frames_allocated = frames_.capacity() * sizeof(FrameNode);
-  size_t frames_resident = frames_.size() * sizeof(FrameNode);
-
-  for (const FrameNode& node : frames_)
-    maps_size += node.children.size() * sizeof(std::pair<StackFrame, int>);
-
+  size_t memory_usage =
+      EstimateMemoryUsage(frames_) + EstimateMemoryUsage(roots_);
   overhead->Add("StackFrameDeduplicator",
-                sizeof(StackFrameDeduplicator) + maps_size + frames_allocated,
-                sizeof(StackFrameDeduplicator) + maps_size + frames_resident);
+                sizeof(StackFrameDeduplicator) + memory_usage);
 }
 
 }  // namespace trace_event

base/trace_event/heap_profiler_stack_frame_deduplicator.h

@@ -34,6 +34,8 @@ class BASE_EXPORT StackFrameDeduplicator : public ConvertableToTraceFormat {
     FrameNode(const FrameNode& other);
     ~FrameNode();
 
+    size_t EstimateMemoryUsage() const;
+
     StackFrame frame;
 
     // The index of the parent stack frame in |frames_|, or -1 if there is no

base/trace_event/heap_profiler_type_name_deduplicator.cc

@@ -12,6 +12,7 @@
 #include "base/json/string_escape.h"
 #include "base/strings/string_split.h"
 #include "base/strings/stringprintf.h"
+#include "base/trace_event/memory_usage_estimator.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_memory_overhead.h"
 
@@ -105,12 +106,9 @@ void TypeNameDeduplicator::AppendAsTraceFormat(std::string* out) const {
 
 void TypeNameDeduplicator::EstimateTraceMemoryOverhead(
     TraceEventMemoryOverhead* overhead) {
-  // The size here is only an estimate; it fails to take into account the size
-  // of the tree nodes for the map, but as an estimate this should be fine.
-  size_t map_size = type_ids_.size() * sizeof(std::pair<const char*, int>);
-
+  size_t memory_usage = EstimateMemoryUsage(type_ids_);
   overhead->Add("TypeNameDeduplicator",
-                sizeof(TypeNameDeduplicator) + map_size);
+                sizeof(TypeNameDeduplicator) + memory_usage);
 }
 
 }  // namespace trace_event