Decouple stability instrumentation recording and collection

components/browser_watcher/watcher_metrics_provider_win.cc

 // Copyright (c) 2014 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 "components/browser_watcher/watcher_metrics_provider_win.h"
 
 #include <stddef.h>
 
 #include <limits>
 #include <memory>
 #include <set>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/feature_list.h"
+#include "base/metrics/field_trial_params.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_base.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/process/process.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/win/registry.h"
 #include "components/browser_watcher/features.h"
@@ skipping 189 matching lines @@
 void WatcherMetricsProviderWin::CollectPostmortemReports(
     const base::Closure& done_callback) {
   io_task_runner_->PostTaskAndReply(
       FROM_HERE,
       base::Bind(
           &WatcherMetricsProviderWin::CollectPostmortemReportsOnBlockingPool,
           weak_ptr_factory_.GetWeakPtr()),
       done_callback);
 }
 
+// TODO(manzagop): consider mechanisms for partial collection if this is to be
+//     used on a critical path.
 void WatcherMetricsProviderWin::CollectPostmortemReportsOnBlockingPool() {
-  // Note: the feature controls both instrumentation and collection.
+  SCOPED_UMA_HISTOGRAM_TIMER("ActivityTracker.Collect.TotalTime");
+
   bool is_stability_debugging_on =
       base::FeatureList::IsEnabled(browser_watcher::kStabilityDebuggingFeature);
   if (!is_stability_debugging_on) {
-    // TODO(manzagop): delete possible leftover data.
-    return;
+    return;  // TODO(manzagop): scan for possible data to delete?
   }
 
-  SCOPED_UMA_HISTOGRAM_TIMER("ActivityTracker.Collect.TotalTime");
-
   if (user_data_dir_.empty() || crash_dir_.empty()) {
-    LOG(ERROR) << "User data directory or crash directory is unknown.";
     LogCollectionInitStatus(UNKNOWN_DIR);
     return;
   }
 
-  // Determine the stability directory and the stability file for the current
-  // process.
+  // Determine which files to harvest.
   base::FilePath stability_dir = GetStabilityDir(user_data_dir_);
+
   base::FilePath current_stability_file;
   if (!GetStabilityFileForProcess(base::Process::Current(), user_data_dir_,
                                   &current_stability_file)) {
-    LOG(ERROR) << "Failed to get the current stability file.";
     LogCollectionInitStatus(GET_STABILITY_FILE_PATH_FAILED);
     return;
   }
-  const std::set<base::FilePath>& excluded_debug_files = {
+  const std::set<base::FilePath>& excluded_stability_files = {
       current_stability_file};
 
+  std::vector<base::FilePath> stability_files = GetStabilityFiles(
+      stability_dir, GetStabilityFilePattern(), excluded_stability_files);
+  UMA_HISTOGRAM_COUNTS_100("ActivityTracker.Collect.StabilityFileCount",
+                           stability_files.size());
+
+  // If postmortem collection is disabled, delete the files.
+  const bool should_collect = base::GetFieldTrialParamByFeatureAsBool(
+      browser_watcher::kStabilityDebuggingFeature,
+      browser_watcher::kCollectPostmortemParam, false);
+  if (!should_collect) {
+    PostmortemDeleter deleter;
+    deleter.Process(stability_files);
+    return;
+  }
+
   // Create a database. Note: Chrome already has a g_database in crashpad.cc but
   // it has internal linkage. Create a new one.
   std::unique_ptr<crashpad::CrashReportDatabase> crashpad_database =
       crashpad::CrashReportDatabase::InitializeWithoutCreating(crash_dir_);
   if (!crashpad_database) {
     LOG(ERROR) << "Failed to initialize a CrashPad database.";
     LogCollectionInitStatus(CRASHPAD_DATABASE_INIT_FAILED);
     return;
   }
 
   LogCollectionInitStatus(INIT_SUCCESS);
 
   // Get the reporter's version details.
   base::string16 product_name, version_number, channel_name;
   exe_details_cb_.Run(&product_name, &version_number, &channel_name);
 
   const size_t kSystemSessionsToInspect = 5U;
   SystemSessionAnalyzer analyzer(kSystemSessionsToInspect);
   PostmortemReportCollector collector(
       base::UTF16ToUTF8(product_name), base::UTF16ToUTF8(version_number),
-      base::UTF16ToUTF8(channel_name), &analyzer);
-  collector.CollectAndSubmitAllPendingReports(
-      stability_dir, GetStabilityFilePattern(), excluded_debug_files,
-      crashpad_database.get());
+      base::UTF16ToUTF8(channel_name), crashpad_database.get(), &analyzer);
+  collector.Process(stability_files);
 }
 
 }  // namespace browser_watcher