[WIP] Add SharedMemoryTracker to dump base::SharedMemory usage

gpu/ipc/client/gpu_memory_buffer_impl_shared_memory.cc

Index: gpu/ipc/client/gpu_memory_buffer_impl_shared_memory.cc
diff --git a/gpu/ipc/client/gpu_memory_buffer_impl_shared_memory.cc b/gpu/ipc/client/gpu_memory_buffer_impl_shared_memory.cc
index 54423d51ceef266fe271be741f8bfa1725b01c56..92b36a30d5d97bf3412de3425070376645e9af4e 100644
--- a/gpu/ipc/client/gpu_memory_buffer_impl_shared_memory.cc
+++ b/gpu/ipc/client/gpu_memory_buffer_impl_shared_memory.cc
@@ -12,7 +12,6 @@
 #include "base/numerics/safe_math.h"
 #include "base/process/memory.h"
 #include "ui/gfx/buffer_format_util.h"
-#include "ui/gfx/gpu_memory_buffer_tracing.h"
 #include "ui/gl/gl_bindings.h"
 
 namespace gpu {
@@ -47,7 +46,8 @@ GpuMemoryBufferImplSharedMemory::Create(gfx::GpuMemoryBufferId id,
   std::unique_ptr<base::SharedMemory> shared_memory(new base::SharedMemory());
   if (!shared_memory->CreateAndMapAnonymous(buffer_size))
     return nullptr;
-
+  const int kImportance = 2;
+  shared_memory->set_importance(kImportance);
   return base::WrapUnique(new GpuMemoryBufferImplSharedMemory(
       id, size, format, callback, std::move(shared_memory), 0,
       gfx::RowSizeForBufferFormat(size.width(), format, 0)));
@@ -86,11 +86,13 @@ GpuMemoryBufferImplSharedMemory::CreateFromHandle(
     gfx::BufferUsage usage,
     const DestructionCallback& callback) {
   DCHECK(base::SharedMemory::IsHandleValid(handle.handle));
-
+  std::unique_ptr<base::SharedMemory> shared_memory =
+      base::MakeUnique<base::SharedMemory>(handle.handle, false);
+  const int kImportance = 2;
+  shared_memory->set_importance(kImportance);
   return base::WrapUnique(new GpuMemoryBufferImplSharedMemory(
-      handle.id, size, format, callback,
-      base::MakeUnique<base::SharedMemory>(handle.handle, false), handle.offset,
-      handle.stride));
+      handle.id, size, format, callback, std::move(shared_memory),
+      handle.offset, handle.stride));
 }
 
 // static
@@ -215,7 +217,11 @@ gfx::GpuMemoryBufferHandle GpuMemoryBufferImplSharedMemory::GetHandle() const {
 base::trace_event::MemoryAllocatorDumpGuid
 GpuMemoryBufferImplSharedMemory::GetGUIDForTracing(
     uint64_t tracing_process_id) const {
-  return gfx::GetSharedMemoryGUIDForTracing(tracing_process_id, id_);
+  return shared_memory_->handle().GetGUIDForTracing();
+}
+
+base::SharedMemory* GpuMemoryBufferImplSharedMemory::GetSharedMemory() {
+  return shared_memory_.get();
 }
 
 }  // namespace gpu