Precache: Optionally rank resources-to-precache globally.

components/precache/core/proto/precache.proto

Index: components/precache/core/proto/precache.proto
diff --git a/components/precache/core/proto/precache.proto b/components/precache/core/proto/precache.proto
index 3f2607df9b4b64d89d438748f91ee4748f264894..666179a55616d777f85e02c2d6c54fbc7447ef86 100644
--- a/components/precache/core/proto/precache.proto
+++ b/components/precache/core/proto/precache.proto
@@ -16,6 +16,10 @@ message PrecacheResource {
 
   // The tophost this resource corresponds to.
   optional string top_host_name = 2;
+
+  // How important this resource is for the host. It ranges from 0.0 to 1.0.
+  // Higher values mean more important.
+  optional double weight_ratio = 3;
 };
 
 message PrecacheManifestId {
@@ -71,7 +75,8 @@ message PrecacheConfigurationSettings {
   repeated string forced_site = 2;
 
   // The number of resources to fetch for each site. Only the top
-  // |top_resources_count| URLs from each manifest are fetched.
+  // |top_resources_count| URLs from each manifest are fetched. Not applicable
+  // if global ranking is enabled.
   optional int32 top_resources_count = 3 [default = 100];
 
   // The maximum number of bytes to download per resource. Downloads of
@@ -89,4 +94,13 @@ message PrecacheConfigurationSettings {
   // day. After this limit is reached, no more resources will be downloaded,
   // until the quota gets replenished the next day.
   optional uint64 daily_quota_total = 6 [default = 40000000 /* 10 MB */];
+
+  // The number of resources to fetch per precache run. Only the first
+  // |total_resources_count| URLs are fetched, regardless of whether global
+  // ranking is enabled.
+  optional uint32 total_resources_count = 7 [default = 999999];
+
+  // The minimum visit-adjusted weight for which a resource will be downloaded.
+  // Only applicable if global ranking is enabled.
+  optional double min_weight = 8 [default = 0];
 };