Remove unused Chrome histograms Net.RDH.RequestMode.*

Bug: 891131
Change-Id: I00c96a302291e4df79810e67e3a50cdf96a7c104
Reviewed-on: https://chromium-review.googlesource.com/c/1350384Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Yutaka Hirano <yhirano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611015}

content/browser/loader/resource_dispatcher_host_impl.cc

@@ -1024,8 +1024,6 @@ void ResourceDispatcherHostImpl::ContinuePendingBeginRequest(
       std::move(url_loader_client));
 
   if (handler) {
-    RecordFetchRequestMode(request_data.url, request_data.method,
-                           request_data.fetch_request_mode);
     const bool is_initiated_by_fetch_api =
         request_data.fetch_request_context_type ==
         static_cast<int>(blink::mojom::RequestContextType::FETCH);
@@ -1601,8 +1599,6 @@ void ResourceDispatcherHostImpl::BeginNavigationRequest(
       -1,  // route_id
       std::move(handler));
 
-  RecordFetchRequestMode(new_request->url(), new_request->method(),
-                         network::mojom::FetchRequestMode::kNavigate);
   BeginRequestInternal(std::move(new_request), std::move(handler),
                        false /* is_initiated_by_fetch_api */,
                        std::move(throttling_token));
@@ -2188,28 +2184,6 @@ void ResourceDispatcherHostImpl::RunAuthRequiredCallback(
   loader->ClearLoginDelegate();
 }
 
-// static
-void ResourceDispatcherHostImpl::RecordFetchRequestMode(
-    const GURL& url,
-    base::StringPiece method,
-    network::mojom::FetchRequestMode mode) {
-  if (!url.SchemeIsHTTPOrHTTPS())
-    return;
-
-  std::string lower_method = base::ToLowerASCII(method);
-  if (lower_method == "get") {
-    UMA_HISTOGRAM_ENUMERATION("Net.ResourceDispatcherHost.RequestMode.Get",
-                              mode);
-  } else if (lower_method == "post") {
-    UMA_HISTOGRAM_ENUMERATION("Net.ResourceDispatcherHost.RequestMode.Post",
-                              mode);
-    if (url.has_port()) {
-      UMA_HISTOGRAM_ENUMERATION(
-          "Net.ResourceDispatcherHost.RequestMode.Post.WithPort", mode);
-    }
-  }
-}
-
 // static
 // We have this function at the bottom of this file because it confuses
 // syntax highliting.

tools/metrics/histograms/histograms.xml

@@ -61302,6 +61302,9 @@ uploading your change for review.
 
 <histogram name="Net.ResourceDispatcherHost.RequestMode.Get"
     enum="FetchRequestMode" expires_after="M69">
+  <obsolete>
+    Removed from code as of 11/2018.
+  </obsolete>
   <owner>yhirano@chromium.org</owner>
   <owner>toyoshim@chromium.org</owner>
   <summary>
@@ -61312,6 +61315,9 @@ uploading your change for review.
 
 <histogram name="Net.ResourceDispatcherHost.RequestMode.Post"
     enum="FetchRequestMode" expires_after="M69">
+  <obsolete>
+    Removed from code as of 11/2018.
+  </obsolete>
   <owner>yhirano@chromium.org</owner>
   <owner>toyoshim@chromium.org</owner>
   <summary>
@@ -61322,6 +61328,9 @@ uploading your change for review.
 
 <histogram name="Net.ResourceDispatcherHost.RequestMode.Post.WithPort"
     enum="FetchRequestMode" expires_after="M69">
+  <obsolete>
+    Removed from code as of 11/2018.
+  </obsolete>
   <owner>yhirano@chromium.org</owner>
   <owner>toyoshim@chromium.org</owner>
   <summary>