[memory-infra] Add support for polling memory totals in MemoryDumpManager

base/trace_event/memory_dump_provider.h

Index: base/trace_event/memory_dump_provider.h
diff --git a/base/trace_event/memory_dump_provider.h b/base/trace_event/memory_dump_provider.h
index c899ea9c3464f9bda11c4f2918425227f2c312d6..0375e0833b7441ca949a8505eab32820883e4dd2 100644
--- a/base/trace_event/memory_dump_provider.h
+++ b/base/trace_event/memory_dump_provider.h
@@ -22,7 +22,8 @@ class BASE_EXPORT MemoryDumpProvider {
   struct Options {
     Options()
         : target_pid(kNullProcessId),
-          dumps_on_single_thread_task_runner(false) {}
+          dumps_on_single_thread_task_runner(false),
+          is_fast_polling_supported(false) {}
 
     // If the dump provider generates dumps on behalf of another process,
     // |target_pid| contains the pid of that process.
@@ -34,6 +35,11 @@ class BASE_EXPORT MemoryDumpProvider {
     // a SingleThreadTaskRunner, which is usually the case. It is faster to run
     // all providers that run on the same thread together without thread hops.
     bool dumps_on_single_thread_task_runner;
+
+    // Set to true if the dump provider implementation supports high frequency
+    // polling. Only providers running without task runner affinity are
+    // supported.
+    bool is_fast_polling_supported;
   };
 
   virtual ~MemoryDumpProvider() {}
@@ -52,6 +58,18 @@ class BASE_EXPORT MemoryDumpProvider {
   // collecting extensive allocation data, if supported.
   virtual void OnHeapProfilingEnabled(bool enabled) {}
 
+  // Quickly record the total memory usage in |memory_total|. This method will
+  // be called only when the dump provider registration has
+  // |is_fast_polling_supported| set to true. This method is used for polling at
+  // high frequency for detecting peaks. See comment on
+  // |is_fast_polling_supported| option if you need to override this method.
+  virtual void PollFastMemoryTotal(uint64_t* memory_total) {}
+
+  // Notifies polling enabled and disabled states. Polling is set enabled before
+  // the first call to PollFastMemoryTotal() and set disabled after the last
+  // call to PollFastMemoryTotal() in a tracing session.
+  virtual void SetFastMemoryPollingEnabled(bool enabled) {}
+
  protected:
   MemoryDumpProvider() {}