Introduce MetricsServiceClient::StartGatheringMetrics

This API is called when initial metrics gathering should start, and takes in a
callback that is called when initial metrics gathering is complete. It is
currently empty but will be filled in as initial metrics gathering code moves
out of MetricsService.

BUG=374231
R=asvitkine@chromium.org

Review URL: https://codereview.chromium.org/299663011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@272479 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/metrics/chrome_metrics_service_client.cc

@@ -5,6 +5,7 @@
 #include "chrome/browser/metrics/chrome_metrics_service_client.h"
 
 #include "base/bind.h"
+#include "base/callback.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
@@ -282,3 +283,9 @@ void ChromeMetricsServiceClient::Observe(
       NOTREACHED();
   }
 }
+
+void ChromeMetricsServiceClient::StartGatheringMetrics(
+    const base::Closure& done_callback) {
+  // TODO(blundell): Move metrics gathering tasks from MetricsService to here.
+  done_callback.Run();
+}

chrome/browser/metrics/chrome_metrics_service_client.h

@@ -34,6 +34,8 @@ class ChromeMetricsServiceClient : public metrics::MetricsServiceClient,
   virtual metrics::SystemProfileProto::Channel GetChannel() OVERRIDE;
   virtual std::string GetVersionString() OVERRIDE;
   virtual void OnLogUploadComplete() OVERRIDE;
+  virtual void StartGatheringMetrics(
+      const base::Closure& done_callback) OVERRIDE;
   virtual void CollectFinalMetrics(const base::Closure& done_callback)
       OVERRIDE;
 

chrome/browser/metrics/metrics_service.cc

@@ -943,6 +943,11 @@ void MetricsService::OpenNewLog() {
     // We only need to schedule that run once.
     state_ = INIT_TASK_SCHEDULED;
 
+    // TODO(blundell): Change the callback to be
+    // FinishedReceivingProfilerData() when the initial metrics gathering is
+    // moved to ChromeMetricsServiceClient.
+    client_->StartGatheringMetrics(base::Bind(&base::DoNothing));
+
     // Schedules a task on the file thread for execution of slower
     // initialization steps (such as plugin list generation) necessary
     // for sending the initial log.  This avoids blocking the main UI

components/metrics/metrics_service_client.h

@@ -42,6 +42,10 @@ class MetricsServiceClient {
   // Called by the metrics service when a log has been uploaded.
   virtual void OnLogUploadComplete() = 0;
 
+  // Starts gathering metrics, calling |done_callback| when initial metrics
+  // gathering is complete.
+  virtual void StartGatheringMetrics(const base::Closure& done_callback) = 0;
+
   // Called prior to a metrics log being closed, allowing the client to collect
   // extra histograms that will go in that log. Asynchronous API - the client
   // implementation should call |done_callback| when complete.

components/metrics/test_metrics_service_client.cc

@@ -45,6 +45,11 @@ std::string TestMetricsServiceClient::GetVersionString() {
 void TestMetricsServiceClient::OnLogUploadComplete() {
 }
 
+void TestMetricsServiceClient::StartGatheringMetrics(
+    const base::Closure& done_callback) {
+  done_callback.Run();
+}
+
 void TestMetricsServiceClient::CollectFinalMetrics(
     const base::Closure& done_callback) {
   done_callback.Run();

components/metrics/test_metrics_service_client.h

@@ -28,6 +28,8 @@ class TestMetricsServiceClient : public MetricsServiceClient {
   virtual SystemProfileProto::Channel GetChannel() OVERRIDE;
   virtual std::string GetVersionString() OVERRIDE;
   virtual void OnLogUploadComplete() OVERRIDE;
+  virtual void StartGatheringMetrics(
+      const base::Closure& done_callback) OVERRIDE;
   virtual void CollectFinalMetrics(const base::Closure& done_callback)
       OVERRIDE;