Add process start time and CPU time columns to task manager

chrome/browser/task_manager/sampling/task_group.h

Index: chrome/browser/task_manager/sampling/task_group.h
diff --git a/chrome/browser/task_manager/sampling/task_group.h b/chrome/browser/task_manager/sampling/task_group.h
index 8013e72c4e00d2b5ddf2944ef5b3de8115cd54aa..b2e8ba9af362849cc42f46e7609d1920cc4fe462 100644
--- a/chrome/browser/task_manager/sampling/task_group.h
+++ b/chrome/browser/task_manager/sampling/task_group.h
@@ -14,6 +14,7 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/process/process_handle.h"
+#include "base/time/time.h"
 #include "build/build_config.h"
 #include "chrome/browser/task_manager/providers/task.h"
 #include "chrome/browser/task_manager/sampling/task_group_sampler.h"
@@ -67,6 +68,8 @@ class TaskGroup {
   bool empty() const { return tasks().empty(); }
 
   double cpu_usage() const { return cpu_usage_; }
+  base::Time start_time() const { return start_time_; }
+  base::TimeDelta cpu_time() const { return cpu_time_; }
   int64_t private_bytes() const { return memory_usage_.private_bytes; }
   int64_t shared_bytes() const { return memory_usage_.shared_bytes; }
   int64_t physical_bytes() const { return memory_usage_.physical_bytes; }
@@ -107,6 +110,10 @@ class TaskGroup {
 
   void OnCpuRefreshDone(double cpu_usage);
 
+  void OnStartTimeRefreshDone(base::Time start_time);
+
+  void OnCpuTimeRefreshDone(base::TimeDelta cpu_time);
+
   void OnPhysicalMemoryUsageRefreshDone(int64_t physical_bytes);
   void OnMemoryUsageRefreshDone(MemoryUsageStats memory_usage);
 
@@ -143,6 +150,8 @@ class TaskGroup {
 
   // The per process resources usages.
   double cpu_usage_;
+  base::Time start_time_;     // Only calculated On Windows now.
+  base::TimeDelta cpu_time_;  // Only calculated On Windows now.
   MemoryUsageStats memory_usage_;
   int64_t gpu_memory_;
   // The network usage in bytes per second as the sum of all network usages of