Randomly enable leak detector based on probability parameter

chrome/browser/metrics/leak_detector/leak_detector_remote_controller.cc

 // Copyright 2016 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 "chrome/browser/metrics/leak_detector/leak_detector_remote_controller.h"
 
 #include "components/metrics/leak_detector/protobuf_to_mojo_converter.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace metrics {
@@ skipping 14 matching lines @@
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   new LeakDetectorRemoteController(std::move(request));
 }
 
 void LeakDetectorRemoteController::GetParams(
     const mojom::LeakDetector::GetParamsCallback& callback) {
   // If no controller exists, send an empty param protobuf. The remote caller
   // should not initialize anything if the params are empty.
   MemoryLeakReportProto_Params params;
   if (g_local_controller) {
-    params = g_local_controller->GetParams();
+    params = g_local_controller->GetParamsAndRecordRequest();
+    // A non-zero sampling rate tells the remote process to enable the leak
+    // detector. Otherwise, the remote process will not initialize it.
+    leak_detector_enabled_on_remote_process_ = params.sampling_rate() > 0;
   }
 
   mojo::StructPtr<mojom::LeakDetectorParams> mojo_params =
       mojom::LeakDetectorParams::New();
   leak_detector::protobuf_to_mojo_converter::ParamsToMojo(params,
                                                           mojo_params.get());
 
   callback.Run(std::move(mojo_params));
 }
 
 void LeakDetectorRemoteController::SendLeakReports(
     std::vector<mojom::MemoryLeakReportPtr> reports) {
   std::vector<MemoryLeakReportProto> report_protos;
   report_protos.reserve(reports.size());
 
   for (const mojom::MemoryLeakReportPtr& report : reports) {
     report_protos.push_back(MemoryLeakReportProto());
     MemoryLeakReportProto* proto = &report_protos.back();
 
     leak_detector::protobuf_to_mojo_converter::MojoToReport(*report, proto);
   }
   DCHECK(g_local_controller);
   g_local_controller->SendLeakReports(report_protos);
 }
 
+void LeakDetectorRemoteController::OnRemoteProcessShutdown() {
+  if (leak_detector_enabled_on_remote_process_) {
+    DCHECK(g_local_controller);
+    g_local_controller->OnRemoteProcessShutdown();
+  }
+}
+
 LeakDetectorRemoteController::LeakDetectorRemoteController(
     mojom::LeakDetectorRequest request)
-    : binding_(this, std::move(request)) {}
+    : binding_(this, std::move(request)),
+      leak_detector_enabled_on_remote_process_(false) {
+  binding_.set_connection_error_handler(
+      base::Bind(&LeakDetectorRemoteController::OnRemoteProcessShutdown,
+                 base::Unretained(this)));
+}
 
 // static
 void LeakDetectorRemoteController::SetLocalControllerInstance(
     LocalController* controller) {
   g_local_controller = controller;
 }
 
 }  // namespace metrics