Add process start time and CPU time columns to task manager

chrome/browser/task_manager/sampling/shared_sampler.h

Index: chrome/browser/task_manager/sampling/shared_sampler.h
diff --git a/chrome/browser/task_manager/sampling/shared_sampler.h b/chrome/browser/task_manager/sampling/shared_sampler.h
index def063488db11eaf4a92a8351dc611ab9a92e96e..86e19ed1ab634d354ec36f861da132cbb4c1d6b2 100644
--- a/chrome/browser/task_manager/sampling/shared_sampler.h
+++ b/chrome/browser/task_manager/sampling/shared_sampler.h
@@ -41,6 +41,8 @@ class SharedSampler : public base::RefCountedThreadSafe<SharedSampler> {
   // These callbacks are passed via RegisterCallbacks.
   using OnIdleWakeupsCallback = base::Callback<void(int)>;
   using OnPhysicalMemoryCallback = base::Callback<void(int64_t)>;
+  using OnStartTimeCallback = base::Callback<void(int64_t)>;
+  using OnCpuTimeCallback = base::Callback<void(int64_t)>;
 
   // Returns a combination of refresh flags supported by the shared sampler.
   int64_t GetSupportedFlags() const;
@@ -48,7 +50,9 @@ class SharedSampler : public base::RefCountedThreadSafe<SharedSampler> {
   // Registers task group specific callbacks.
   void RegisterCallbacks(base::ProcessId process_id,
                          const OnIdleWakeupsCallback& on_idle_wakeups,
-                         const OnPhysicalMemoryCallback& on_physical_memory);
+                         const OnPhysicalMemoryCallback& on_physical_memory,
+                         const OnStartTimeCallback& on_start_time,
+                         const OnCpuTimeCallback& on_cpu_time);
 
   // Unregisters task group specific callbacks.
   void UnregisterCallbacks(base::ProcessId process_id);
@@ -71,6 +75,8 @@ class SharedSampler : public base::RefCountedThreadSafe<SharedSampler> {
 
     OnIdleWakeupsCallback on_idle_wakeups;
     OnPhysicalMemoryCallback on_physical_memory;
+    OnStartTimeCallback on_start_time;
+    OnCpuTimeCallback on_cpu_time;
 
    private:
     DISALLOW_COPY_AND_ASSIGN(Callbacks);
@@ -83,6 +89,8 @@ class SharedSampler : public base::RefCountedThreadSafe<SharedSampler> {
     base::ProcessId process_id;
     int idle_wakeups_per_second;
     int64_t physical_bytes;
+    int64_t start_time;

[brucedawson, 2016/12/19 21:51:05]

Should these be using a type that includes semantic information about units?
It's not clear what the units of start_time or cpu_time are. Right now these
need a comment, but using an appropriate type could avoid that.

It looks like these are using the wacky Windows 100 ns units, which is fine, but
does require a comment. Also should consider using uint64_t to avoid casts -
it's equivalent to ULONGLONG.

[chengx, 2016/12/20 00:51:12]

Done.

+    int64_t cpu_time;
   };
 
   typedef std::vector<RefreshResult> RefreshResults;