Display histograms from subprocesses in chrome://histograms

base/metrics/statistics_recorder.cc

 // Copyright (c) 2012 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 "base/metrics/statistics_recorder.h"
 
 #include <memory>
+#include <set>
 
 #include "base/at_exit.h"
 #include "base/debug/leak_annotations.h"
 #include "base/json/string_escape.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/metrics_hashes.h"
 #include "base/metrics/persistent_histogram_allocator.h"
 #include "base/stl_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/synchronization/lock.h"
 #include "base/values.h"
 
 namespace {
 
 // Initialize histogram statistics gathering system.
 base::LazyInstance<base::StatisticsRecorder>::Leaky g_statistics_recorder_ =
     LAZY_INSTANCE_INITIALIZER;
 
 bool HistogramNameLesser(const base::HistogramBase* a,
                          const base::HistogramBase* b) {
   return a->histogram_name() < b->histogram_name();
 }
 
+base::LazyInstance<std::set<base::StatisticsRecorder::MetricsDisplayer*>>::Leaky
+    g_metrics_displayers_ = LAZY_INSTANCE_INITIALIZER;
+
 }  // namespace
 
 namespace base {
 
 StatisticsRecorder::HistogramIterator::HistogramIterator(
     const HistogramMap::iterator& iter, bool include_persistent)
     : iter_(iter),
       include_persistent_(include_persistent) {
   // The starting location could point to a persistent histogram when such
   // is not wanted. If so, skip it.
@@ skipping 162 matching lines @@
 // static
 void StatisticsRecorder::WriteHTMLGraph(const std::string& query,
                                         std::string* output) {
   if (!IsActive())
     return;
 
   Histograms snapshot;
   GetSnapshot(query, &snapshot);
   std::sort(snapshot.begin(), snapshot.end(), &HistogramNameLesser);
   for (const HistogramBase* histogram : snapshot) {
-    histogram->WriteHTMLGraph(output);
+    histogram->WriteHTMLGraph(nullptr, output);
     output->append("<br><hr><br>");
   }
+
+  for (auto display : g_metrics_displayers_.Get()) {
+    output->append("<hr size=10 noshade><br><hr><br>\n<p>");
+    display->WriteTitleString(output);
+    output->append("</p>\n");
+    display->WriteGraphs(query, MetricsDisplayer::DISPLAY_TEXT_HTML, output);
+  }
 }
 
 // static
 void StatisticsRecorder::WriteGraph(const std::string& query,
                                     std::string* output) {
   if (!IsActive())
     return;
   if (query.length())
     StringAppendF(output, "Collections of histograms for %s\n", query.c_str());
   else
     output->append("Collections of all histograms\n");
 
   Histograms snapshot;
   GetSnapshot(query, &snapshot);
   std::sort(snapshot.begin(), snapshot.end(), &HistogramNameLesser);
   for (const HistogramBase* histogram : snapshot) {
-    histogram->WriteAscii(output);
+    histogram->WriteAscii(nullptr, output);
     output->append("\n");
   }
+
+  for (auto display : g_metrics_displayers_.Get()) {
+    output->append(
+        "########################################"
+        "########################################\n\n");
+    display->WriteTitleString(output);
+    output->append("\n\n");
+    display->WriteGraphs(query, MetricsDisplayer::DISPLAY_TEXT_PLAIN, output);
+  }
 }
 
 // static
 std::string StatisticsRecorder::ToJSON(const std::string& query) {
   if (!IsActive())
     return std::string();
 
   std::string output("{");
   if (!query.empty()) {
     output += "\"query\":";
@@ skipping 162 matching lines @@
   if (!lock_)
     return 0;
 
   base::AutoLock auto_lock(*lock_);
   if (!histograms_)
     return 0;
   return histograms_->size();
 }
 
 // static
+void StatisticsRecorder::RegisterMetricsDisplayer(MetricsDisplayer* display) {
+  DCHECK(!ContainsKey(g_metrics_displayers_.Get(), display));
+  g_metrics_displayers_.Get().insert(display);
+}
+
+// static
+void StatisticsRecorder::DeregisterMetricsDisplayer(MetricsDisplayer* display) {
+  DCHECK(ContainsKey(g_metrics_displayers_.Get(), display));
+  g_metrics_displayers_.Get().erase(display);
+}
+
+// static
 void StatisticsRecorder::ForgetHistogramForTesting(base::StringPiece name) {
   if (histograms_)
     histograms_->erase(name);
 }
 
 // static
 void StatisticsRecorder::UninitializeForTesting() {
   // Stop now if it's never been initialized.
   if (lock_ == NULL || histograms_ == NULL)
     return;
@@ skipping 85 matching lines @@
 // static
 StatisticsRecorder::HistogramMap* StatisticsRecorder::histograms_ = NULL;
 // static
 StatisticsRecorder::CallbackMap* StatisticsRecorder::callbacks_ = NULL;
 // static
 StatisticsRecorder::RangesMap* StatisticsRecorder::ranges_ = NULL;
 // static
 base::Lock* StatisticsRecorder::lock_ = NULL;
 
 }  // namespace base