[GRC] Tab-level CPU Attribution

services/resource_coordinator/coordination_unit/web_contents_coordination_unit_impl.cc

Index: services/resource_coordinator/coordination_unit/web_contents_coordination_unit_impl.cc
diff --git a/services/resource_coordinator/coordination_unit/web_contents_coordination_unit_impl.cc b/services/resource_coordinator/coordination_unit/web_contents_coordination_unit_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e5b840abd31e4aa3820a4a846d90b7fba161f850
--- /dev/null
+++ b/services/resource_coordinator/coordination_unit/web_contents_coordination_unit_impl.cc
@@ -0,0 +1,84 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "services/resource_coordinator/coordination_unit/web_contents_coordination_unit_impl.h"
+
+#include <utility>
+
+namespace service_manager {
+class ServiceContextRef;
+}
+
+namespace resource_coordinator {
+
+struct CoordinationUnitID;
+
+WebContentsCoordinationUnitImpl::WebContentsCoordinationUnitImpl(
+    const CoordinationUnitID& id,
+    std::unique_ptr<service_manager::ServiceContextRef> service_ref)
+    : CoordinationUnitImpl(id, std::move(service_ref)) {}
+
+WebContentsCoordinationUnitImpl::~WebContentsCoordinationUnitImpl() = default;
+
+std::set<CoordinationUnitImpl*>
+WebContentsCoordinationUnitImpl::GetAssociatedCoordinationUnitsOfType(
+    CoordinationUnitType type) {
+  switch (type) {
+    case CoordinationUnitType::kProcess: {
+      std::set<CoordinationUnitImpl*> process_coordination_units;
+
+      // There is currently not a direct relationship between processes and
+      // tabs. However, frames are children of both processes and frames, so we
+      // find all of the processes that are reachable from the tabs's child
+      // frames.
+      for (auto* frame_coordination_unit :
+           GetChildCoordinationUnitsOfType(CoordinationUnitType::kFrame)) {
+        for (auto* process_coordination_unit :
+             frame_coordination_unit->GetAssociatedCoordinationUnitsOfType(
+                 CoordinationUnitType::kProcess)) {
+          process_coordination_units.insert(process_coordination_unit);
+        }
+      }
+
+      return process_coordination_units;
+    }
+    case CoordinationUnitType::kFrame:
+      return GetChildCoordinationUnitsOfType(type);
+    default:
+      return std::set<CoordinationUnitImpl*>();
+  }
+}
+
+double WebContentsCoordinationUnitImpl::CalculateCPUUsage() {
+  double cpu_usage = 0.0;
+
+  for (auto* process_coordination_unit :
+       GetAssociatedCoordinationUnitsOfType(CoordinationUnitType::kProcess)) {
+    size_t tabs_in_process = process_coordination_unit
+                                 ->GetAssociatedCoordinationUnitsOfType(
+                                     CoordinationUnitType::kWebContents)
+                                 .size();
+    DCHECK_LE(1u, tabs_in_process);
+
+    base::Value process_cpu_usage_value =
+        process_coordination_unit->GetProperty(mojom::PropertyType::kCPUUsage);
+    double process_cpu_usage =
+        process_cpu_usage_value.IsType(base::Value::Type::NONE)
+            ? 0.0
+            : process_cpu_usage_value.GetDouble();
+    cpu_usage += process_cpu_usage / tabs_in_process;
+  }
+
+  return cpu_usage;
+}
+
+void WebContentsCoordinationUnitImpl::RecalculateProperty(
+    mojom::PropertyType property_type) {
+  if (property_type == mojom::PropertyType::kCPUUsage) {
+    double cpu_usage = CalculateCPUUsage();
+    SetProperty(mojom::PropertyType::kCPUUsage, base::Value(cpu_usage));
+  }
+}
+
+}  // namespace resource_coordinator