Add new SampledProfile protobuf definition

components/metrics/proto/chrome_user_metrics_extension.proto

Index: components/metrics/proto/chrome_user_metrics_extension.proto
diff --git a/components/metrics/proto/chrome_user_metrics_extension.proto b/components/metrics/proto/chrome_user_metrics_extension.proto
index 80f34996fc90f589807cfed9d0b490ec668ec19f..7efa5b4c7dbe309b01c81a11344f52544b05e8fa 100644
--- a/components/metrics/proto/chrome_user_metrics_extension.proto
+++ b/components/metrics/proto/chrome_user_metrics_extension.proto
@@ -16,8 +16,9 @@ import "profiler_event.proto";
 import "system_profile.proto";
 import "user_action_event.proto";
 import "perf_data.proto";
+import "sampled_profile.proto";
 
-// Next tag: 11
+// Next tag: 12
 message ChromeUserMetricsExtension {
   // The product (i.e. end user application) for a given UMA log.
   enum Product {
@@ -54,5 +55,9 @@ message ChromeUserMetricsExtension {
   repeated HistogramEventProto histogram_event = 6;
   repeated ProfilerEventProto profiler_event = 7;
 
+  // TODO(sque): Deprecate this field and use |sampled_profile| instead.
   repeated PerfDataProto perf_data = 8;
+
+  // A list of all collected sample-based profiles since the last UMA upload.
+  repeated SampledProfile sampled_profile = 11;
 }