[tracing] Implement composable memory usage estimators.

ui/android/resources/resource_manager_impl.cc

Index: ui/android/resources/resource_manager_impl.cc
diff --git a/ui/android/resources/resource_manager_impl.cc b/ui/android/resources/resource_manager_impl.cc
index 0f8fbdf7037cc6f0c27798865a6afb41b3557b26..11e27804cfd3154ca4b14d4bb2909d144047bff3 100644
--- a/ui/android/resources/resource_manager_impl.cc
+++ b/ui/android/resources/resource_manager_impl.cc
@@ -15,6 +15,7 @@
 #include "base/memory/ptr_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/threading/thread_task_runner_handle.h"
+#include "base/trace_event/estimate_memory_usage.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/process_memory_dump.h"
 #include "base/trace_event/trace_event.h"
@@ -300,31 +301,18 @@ ResourceManagerImpl::ProcessCrushedSpriteFrameRects(
 bool ResourceManagerImpl::OnMemoryDump(
     const base::trace_event::MemoryDumpArgs& args,
     base::trace_event::ProcessMemoryDump* pmd) {
-  size_t size = 0;
-  for (const auto& resource_map : resources_) {
-    for (const auto& id_and_resource : resource_map) {
-      if (id_and_resource.second && id_and_resource.second->ui_resource)
-        size += id_and_resource.second->ui_resource->GetAllocatedSizeInBytes();
-    }
-  }
-  for (const auto& id_and_resource : crushed_sprite_resources_) {
-    if (id_and_resource.second)
-      size += id_and_resource.second->GetAllocatedSizeInBytes();
-  }
-  for (const auto& color_and_resources : tinted_resources_) {
-    for (const auto& id_and_resource : *color_and_resources.second) {
-      if (id_and_resource.second && id_and_resource.second->ui_resource)
-        size += id_and_resource.second->ui_resource->GetAllocatedSizeInBytes();
-    }
-  }
+  using base::trace_event::EstimateMemoryUsage;
+  size_t memory_usage = EstimateMemoryUsage(resources_) +
+                        EstimateMemoryUsage(crushed_sprite_resources_) +
+                        EstimateMemoryUsage(tinted_resources_);
 
   base::trace_event::MemoryAllocatorDump* dump = pmd->CreateAllocatorDump(
       base::StringPrintf("ui/resource_manager_0x%" PRIXPTR,
                          reinterpret_cast<uintptr_t>(this)));
   dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
-                  base::trace_event::MemoryAllocatorDump::kUnitsBytes, size);
+                  base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                  memory_usage);
 
-  // Bitmaps are allocated from malloc.
   const char* system_allocator_name =
       base::trace_event::MemoryDumpManager::GetInstance()
           ->system_allocator_pool_name();