Add process lifetime annotations to stack samples.

components/metrics/proto/call_stack_profile.proto

Index: components/metrics/proto/call_stack_profile.proto
diff --git a/components/metrics/proto/call_stack_profile.proto b/components/metrics/proto/call_stack_profile.proto
index e41b3390224ab8561f2285d7bd36217d990475ef..06253e2696481de0e2e6fb48d773c60504a51c0d 100644
--- a/components/metrics/proto/call_stack_profile.proto
+++ b/components/metrics/proto/call_stack_profile.proto
@@ -32,6 +32,17 @@ message CallStackProfile {
 
     // Number of times this stack signature occurs.
     optional int64 count = 2;
+
+    // This bit-field provide information about the current phase of the system
+    // such as whether it is in startup, general operation, or shutdown. This
+    // field is not present if it is unchanged from the previous Sample.
+    optional fixed32 process_phases = 3;
+
+    // This bit-field provide information about current activities of the system
+    // such as whether it is (for example) writing out profile information or
+    // uploading metrics. This field is not present if it is unchanged from the
+    // previous Sample.
+    optional fixed32 current_activities = 4;
   }
 
   // Uniquely identifies a module.