predictors: Refactor resource_prefetch_predictor_tables.

chrome/browser/predictors/resource_prefetch_predictor.proto

Index: chrome/browser/predictors/resource_prefetch_predictor.proto
diff --git a/chrome/browser/predictors/resource_prefetch_predictor.proto b/chrome/browser/predictors/resource_prefetch_predictor.proto
index 6d2a59be1a5bf56905c926b4bb44a4ef367e4a11..18e9c99e32024c380b22b022bd04c0c465368eee 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor.proto
+++ b/chrome/browser/predictors/resource_prefetch_predictor.proto
@@ -18,6 +18,7 @@ message Metadata {
   optional uint64 last_visit_time = 2;
 }
 
+// Represents information about single subresource.

[Benoit L, 2016/10/04 15:43:57]

nit: Represents a single subresource.

[alexilin, 2016/10/04 17:25:46]

Done.

 message ResourceData {
   // Mirrors content::ResourceType.
   enum ResourceType {
@@ -62,6 +63,14 @@ message ResourceData {
   optional bool always_revalidate = 9;
 }
 
+// Represents collection of subresources associated with URL or host.

[Benoit L, 2016/10/04 15:43:57]

nit: Represents a collection of subresources associated with a URL or host.

[alexilin, 2016/10/04 17:25:46]

Done.

+message PrefetchData {
+  // Represents main frame URL of host.

[Benoit L, 2016/10/04 15:43:57]

nit: Main frame URL or host.

[alexilin, 2016/10/04 17:25:46]

Done.

+  optional string primary_key = 1;
+  optional uint64 last_visit_time = 2;
+  repeated ResourceData resources = 3;
+}
+
 // Represents a mapping from URL or host to a list of redirect endpoints.
 message RedirectData {
   // Represents a single redirect chain endpoint.