Fix global dumps to be dumped only when shared memory is actually used

gpu/command_buffer/service/buffer_manager.cc

Index: gpu/command_buffer/service/buffer_manager.cc
diff --git a/gpu/command_buffer/service/buffer_manager.cc b/gpu/command_buffer/service/buffer_manager.cc
index 4469af8f2edde71928f86ee080007303eda04c91..b37285e688ae84c464c00af38ce8c20ed4b19294 100644
--- a/gpu/command_buffer/service/buffer_manager.cc
+++ b/gpu/command_buffer/service/buffer_manager.cc
@@ -737,10 +737,13 @@ bool BufferManager::OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
                     MemoryAllocatorDump::kUnitsBytes,
                     static_cast<uint64_t>(buffer->size()));
 
-    auto guid = gl::GetGLBufferGUIDForTracing(share_group_tracing_guid,
-                                              client_buffer_id);
-    pmd->CreateSharedGlobalAllocatorDump(guid);
-    pmd->AddOwnershipEdge(dump->guid(), guid);
+    auto* mapped_range = buffer->GetMappedRange();
+    if (mapped_range && mapped_range->shm->backing()->is_shared()) {
+      auto guid = gl::GetGLBufferGUIDForTracing(share_group_tracing_guid,
+                                                client_buffer_id);
+      pmd->CreateSharedGlobalAllocatorDump(guid);
+      pmd->AddOwnershipEdge(dump->guid(), guid);
+    }
   }
 
   return true;