RC: Fire OnProcessCPUUsageReady after a CPU measurement cycle.

Also rearrange method order a little and rename HandleMetrics to
DispatchMetrics, as there's no need to pass the metrics map to the
method.

R=chrisha@chromium.org

Bug: 755840
Change-Id: If316817f540315bf8c0465d1d32be60734183db6
Reviewed-on: https://chromium-review.googlesource.com/1019563Reviewed-by: Chris Hamilton <chrisha@chromium.org>
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553066}

chrome/browser/resource_coordinator/resource_coordinator_render_process_probe.cc

@@ -14,6 +14,7 @@
 #include "content/public/common/service_manager_connection.h"
 #include "services/resource_coordinator/public/cpp/process_resource_coordinator.h"
 #include "services/resource_coordinator/public/cpp/resource_coordinator_features.h"
+#include "services/resource_coordinator/public/cpp/system_resource_coordinator.h"
 #include "services/resource_coordinator/public/mojom/coordination_unit.mojom.h"
 
 #if defined(OS_MACOSX)
@@ -150,33 +151,13 @@ void ResourceCoordinatorRenderProcessProbe::
   DCHECK(is_gathering_);
   is_gathering_ = false;
 
-  if (HandleMetrics(render_process_info_map_)) {
+  if (DispatchMetrics()) {
     timer_.Start(FROM_HERE, interval_, this,
                  &ResourceCoordinatorRenderProcessProbe::
                      RegisterAliveRenderProcessesOnUIThread);
   }
 }
 
-bool ResourceCoordinatorRenderProcessProbe::HandleMetrics(
-    const RenderProcessInfoMap& render_process_info_map) {
-  for (auto& render_process_info_map_entry : render_process_info_map) {
-    auto& render_process_info = render_process_info_map_entry.second;
-    // TODO(oysteine): Move the multiplier used to avoid precision loss
-    // into a shared location, when this property gets used.
-
-    // Note that the RPH may have been deleted while the CPU metrics were
-    // acquired on a blocking thread.
-    content::RenderProcessHost* host = content::RenderProcessHost::FromID(
-        render_process_info.render_process_host_id);
-    if (host) {
-      host->GetProcessResourceCoordinator()->SetCPUUsage(
-          render_process_info.cpu_usage);
-    }
-  }
-
-  return true;
-}
-
 void ResourceCoordinatorRenderProcessProbe::UpdateWithFieldTrialParams() {
   int64_t interval_ms = GetGRCRenderProcessCPUProfilingIntervalInMs();
 
@@ -185,4 +166,48 @@ void ResourceCoordinatorRenderProcessProbe::UpdateWithFieldTrialParams() {
   }
 }
 
+SystemResourceCoordinator*
+ResourceCoordinatorRenderProcessProbe::EnsureSystemResourceCoordinator() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  if (!system_resource_coordinator_) {
+    content::ServiceManagerConnection* connection =
+        content::ServiceManagerConnection::GetForProcess();
+    if (connection)
+      system_resource_coordinator_ =
+          std::make_unique<SystemResourceCoordinator>(
+              connection->GetConnector());
+  }
+
+  return system_resource_coordinator_.get();
+}
+
+bool ResourceCoordinatorRenderProcessProbe::DispatchMetrics() {
+  SystemResourceCoordinator* system_resource_coordinator =
+      EnsureSystemResourceCoordinator();
+
+  if (system_resource_coordinator) {
+    bool dispatched_measurement = false;
+    for (auto& render_process_info_map_entry : render_process_info_map_) {
+      auto& render_process_info = render_process_info_map_entry.second;
+      // TODO(oysteine): Move the multiplier used to avoid precision loss
+      // into a shared location, when this property gets used.
+
+      // Note that the RPH may have been deleted while the CPU metrics were
+      // acquired on a blocking thread.
+      content::RenderProcessHost* host = content::RenderProcessHost::FromID(
+          render_process_info.render_process_host_id);
+      if (host) {
+        dispatched_measurement = true;
+        host->GetProcessResourceCoordinator()->SetCPUUsage(
+            render_process_info.cpu_usage);
+      }
+    }
+
+    if (dispatched_measurement)
+      system_resource_coordinator->OnProcessCPUUsageReady();
+  }
+
+  return true;
+}
+
 }  // namespace resource_coordinator

chrome/browser/resource_coordinator/resource_coordinator_render_process_probe.h

@@ -17,6 +17,8 @@
 
 namespace resource_coordinator {
 
+class SystemResourceCoordinator;
+
 struct RenderProcessInfo {
   RenderProcessInfo();
   ~RenderProcessInfo();
@@ -68,13 +70,17 @@ class ResourceCoordinatorRenderProcessProbe {
   // consists of a delayed call to perform (1) via a timer.
   void HandleRenderProcessMetricsOnUIThread();
 
-  // Handle collected metrics. Returns |true| another metrics collection gather
-  // cycle should be initiated. Virtual for testing.
+  // Allows FieldTrial parameters to override defaults.
+  void UpdateWithFieldTrialParams();
+
+  SystemResourceCoordinator* EnsureSystemResourceCoordinator();
+
+  // Dispatch the collected metrics. Returns |true| if another metrics
+  // collection gather cycle should be initiated. Virtual for testing.
   // Default implementation sends collected metrics back to the resource
   // coordinator service and initiates another render process metrics gather
   // cycle.
-  virtual bool HandleMetrics(
-      const RenderProcessInfoMap& render_process_info_map);
+  virtual bool DispatchMetrics();
 
   // A map of currently running render process host IDs to Process.
   RenderProcessInfoMap render_process_info_map_;
@@ -92,8 +98,8 @@ class ResourceCoordinatorRenderProcessProbe {
   // True while a gathering cycle is underways on a background thread.
   bool is_gathering_ = false;
 
-  // Allows FieldTrial parameters to override defaults.
-  void UpdateWithFieldTrialParams();
+  // Used to signal the end of a CPU measurement cycle to the RC.
+  std::unique_ptr<SystemResourceCoordinator> system_resource_coordinator_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourceCoordinatorRenderProcessProbe);
 };

chrome/browser/resource_coordinator/resource_coordinator_render_process_probe_browsertest.cc

@@ -30,8 +30,7 @@ class TestingResourceCoordinatorRenderProcessProbe
   TestingResourceCoordinatorRenderProcessProbe() = default;
   ~TestingResourceCoordinatorRenderProcessProbe() override = default;
 
-  bool HandleMetrics(
-      const RenderProcessInfoMap& render_process_info_map) override {
+  bool DispatchMetrics() override {
     current_run_loop_->QuitWhenIdle();
     return false;
   }