Deprecate hints proto fields that are not called by the client and will not be anymore

Change-Id: I1e8ea40a585589bf0ec3781897b498dd94a28d25
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2028260Reviewed-by: Michael Crouse <mcrouse@chromium.org>
Commit-Queue: Sophie Chang <sophiechang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738028}

chrome/browser/optimization_guide/optimization_guide_hints_manager_unittest.cc

@@ -579,7 +579,7 @@ TEST_F(OptimizationGuideHintsManagerTest, ParseTwoConfigVersions) {
   optimization1->set_optimization_type(
       optimization_guide::proto::RESOURCE_LOADING);
   optimization_guide::proto::ResourceLoadingHint* resource_loading_hint1 =
-      optimization1->add_resource_loading_hints();
+      optimization1->mutable_previews_metadata()->add_resource_loading_hints();
   resource_loading_hint1->set_loading_optimization_type(
       optimization_guide::proto::LOADING_BLOCK_RESOURCE);
   resource_loading_hint1->set_resource_pattern("news_cruft.js");

components/optimization_guide/proto/hints.proto

@@ -57,6 +57,8 @@ message GetHintsRequest {
 
 // Response to the GetHints request.
 message GetHintsResponse {
+  reserved 2;
+
   // An ordered list containing hints for key/optimization combinations.
   //
   // It is guaranteed that there will only be a single hint per key and key
@@ -71,10 +73,6 @@ message GetHintsResponse {
   // hints from (HOST_SUFFIX,sports.cnn.com).
   repeated Hint hints = 1;
 
-  // The maximum duration in which the hints provided in this response should
-  // be retained in the client cache.
-  optional Duration max_cache_duration = 2 [deprecated = true];
-
   // A set of hint keys to remove from the client cache.
   //
   // It is guaranteed that all entries in this list were provided by the client
@@ -148,23 +146,9 @@ enum KeyRepresentation {
 }
 
 message Optimization {
+  reserved 2, 3;
   // The type of optimization the hint applies to.
   optional OptimizationType optimization_type = 1;
-  // A percent value to inflate the number of received bytes by for the purposes
-  // of data savings calculations in the client.
-  //
-  // If this value is set to 0, the client should use its configured default.
-  //
-  // Ex: If the received bytes is 100 and the inflation_percent is 30, the
-  // inflated bytes calculated by the client will be 30 in order to have a total
-  // consumed bytes value of 130.
-  optional int64 inflation_percent = 2 [deprecated = true];
-  // An ordered set of resource loading hints for OptimizationType
-  // RESOURCE_LOADING.
-  //
-  // Only the first ResourceLoadingHint record that matches a target resource
-  // URL will be applied to that resource.
-  repeated ResourceLoadingHint resource_loading_hints = 3 [deprecated = true];
   // The experiment name that activates the optimization.
   //
   // If a non-empty name is provided, the optimization will be disabled unless