Fix CPM casting issue; refactor renderer crash events

chrome/browser/performance_monitor/metric.h

 // 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.
 
 #ifndef CHROME_BROWSER_PERFORMANCE_MONITOR_METRIC_H_
 #define CHROME_BROWSER_PERFORMANCE_MONITOR_METRIC_H_
 
 #include <string>
 #include "base/time.h"
 
 namespace performance_monitor {
 
 // IMPORTANT: To add new metrics, please
 // - Place the new metric above METRIC_NUMBER_OF_METRICS.
 // - Add a member to the MetricKeyChar enum in key_builder.cc.
 // - Add the appropriate messages in generated_resources.grd.
 // - Add the appropriate functions in
 //   chrome/browser/ui/webui/performance_monitor/performance_monitor_l10n.h.
 enum MetricType {
-METRIC_UNDEFINED,
-METRIC_CPU_USAGE,
-METRIC_PRIVATE_MEMORY_USAGE,
-METRIC_SHARED_MEMORY_USAGE,
-METRIC_STARTUP_TIME,
-METRIC_TEST_STARTUP_TIME,
-METRIC_SESSION_RESTORE_TIME,
-METRIC_PAGE_LOAD_TIME,
-METRIC_NETWORK_BYTES_READ,
-METRIC_NUMBER_OF_METRICS
+  METRIC_UNDEFINED,
+
+  // CPU and memory usage are combined for all Chrome-related processes.
+  METRIC_CPU_USAGE,
+  METRIC_PRIVATE_MEMORY_USAGE,
+  METRIC_SHARED_MEMORY_USAGE,
+
+  // Timing measurements; these are all independent metrics (e.g., session
+  // restore time is independent of startup time, even though they may happen
+  // in sequence). Test startup time refers to any non-normal startup time, e.g.
+  // when we run test suites.
+  METRIC_STARTUP_TIME,
+  METRIC_TEST_STARTUP_TIME,
+  METRIC_SESSION_RESTORE_TIME,
+  METRIC_PAGE_LOAD_TIME,
+
+  // Total number of bytes read since PerformanceMonitor first started running.
+  METRIC_NETWORK_BYTES_READ,
+
+  METRIC_NUMBER_OF_METRICS
 };
 
 struct Metric {
  public:
   Metric();
   Metric(MetricType metric_type,
          const base::Time& metric_time,
          const double metric_value);
   Metric(MetricType metric_type,
          const std::string& metric_time,
@@ skipping 11 matching lines @@
   std::string ValueAsString() const;
 
   MetricType type;
   base::Time time;
   double value;
 };
 
 }  // namespace performance_monitor
 
 #endif  // CHROME_BROWSER_PERFORMANCE_MONITOR_METRIC_H_