NotForReview: Expose the global memory budget (chromium side)

content/child/memory/child_memory_coordinator_impl.cc

Index: content/child/memory/child_memory_coordinator_impl.cc
diff --git a/content/child/memory/child_memory_coordinator_impl.cc b/content/child/memory/child_memory_coordinator_impl.cc
index 6616a22e1b7d320a2aeb5339914c886f8b7eae54..3100962a1629c6cb9aea530b3d3418c7ec1441b3 100644
--- a/content/child/memory/child_memory_coordinator_impl.cc
+++ b/content/child/memory/child_memory_coordinator_impl.cc
@@ -50,6 +50,9 @@ ChildMemoryCoordinatorImpl::ChildMemoryCoordinatorImpl(
   DCHECK(!g_child_memory_coordinator);
   g_child_memory_coordinator = this;
   parent_->AddChild(binding_.CreateInterfacePtrAndBind());
+  parent_->GetGlobalBudgetHandle(
+      base::Bind(&ChildMemoryCoordinatorImpl::OnGetGlobalBudgetHandle,
+                 base::Unretained(this)));
   base::MemoryCoordinatorProxy::SetMemoryCoordinator(this);
 }
 
@@ -63,6 +66,17 @@ base::MemoryState ChildMemoryCoordinatorImpl::GetCurrentMemoryState() const {
   return current_state_;
 }
 
+int64_t ChildMemoryCoordinatorImpl::GetGlobalBudget() {
+  if (!global_budget_handle_.is_valid())
+    return -1;
+  return *reinterpret_cast<int64_t*>(global_budget_mapping_.get());
+}
+
+void ChildMemoryCoordinatorImpl::SetGlobalBudgetUpdateInterval(
+    uint32_t interval_ms) {
+  parent_->SetGlobalBudgetUpdateInterval(interval_ms);
+}
+
 void ChildMemoryCoordinatorImpl::PurgeMemory() {
   TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("memory-infra"),
                "ChildMemoryCoordinatorImpl::PurgeMemory");
@@ -77,6 +91,13 @@ void ChildMemoryCoordinatorImpl::OnStateChange(mojom::MemoryState state) {
   base::MemoryCoordinatorClientRegistry::GetInstance()->Notify(current_state_);
 }
 
+void ChildMemoryCoordinatorImpl::OnGetGlobalBudgetHandle(
+    mojo::ScopedSharedBufferHandle handle) {
+  global_budget_handle_ = std::move(handle);
+  global_budget_mapping_ = global_budget_handle_->Map(sizeof(int64_t));
+  DCHECK(global_budget_mapping_.get());
+}
+
 #if !defined(OS_ANDROID)
 std::unique_ptr<ChildMemoryCoordinatorImpl> CreateChildMemoryCoordinator(
     mojom::MemoryCoordinatorHandlePtr parent,