Revert "Make mime type sniffing in DevToolsURLLoaderInterceptor consi…

…stent with real URLLoader"

This reverts commit 918d412.

Reason for revert:
http/tests/inspector-protocol/fetch/mime-type-sniffing.js consistently failing on linux-trusty-rel. Regression began when this change landed: https://ci.chromium.org/ui/p/chromium/builders/ci/linux-trusty-rel/24163/blamelist

Original change's description:
> Make mime type sniffing in DevToolsURLLoaderInterceptor consistent with real URLLoader
>
> - extract ShouldSniffContent() from url_loader.cc to header_util.{h,cc}
> - reuse it in DevToolsURLLoaderInterceptor
>
> Bug: b/187745024
> Change-Id: I0cd6904e7912c372aa744b0abb038d867c9195d2
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2905075
> Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
> Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#884328}

Bug: b/187745024,1210841
Change-Id: I73260f7b6fe85d323eba0946c5386becab4c898c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2910515
Owners-Override: Katie Dektar <katie@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Katie Dektar <katie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#885087}

content/browser/devtools/devtools_url_loader_interceptor.cc

@@ -35,7 +35,6 @@
 #include "net/url_request/redirect_util.h"
 #include "net/url_request/referrer_policy.h"
 #include "services/network/public/cpp/cors/cors.h"
-#include "services/network/public/cpp/header_util.h"
 #include "services/network/public/cpp/resource_request_body.h"
 #include "services/network/public/mojom/network_context.mojom.h"
 #include "third_party/blink/public/platform/resource_request_blocked_reason.h"
@@ -1038,22 +1037,15 @@ Response InterceptionJob::ProcessResponseOverride(
         base::MakeRefCounted<net::HttpResponseHeaders>(kDummyHeaders);
   }
   head->headers->GetMimeTypeAndCharset(&head->mime_type, &head->charset);
-  const GURL& url = create_loader_params_->request.url;
-  if (create_loader_params_->options &
-      network::mojom::kURLLoadOptionSniffMimeType) {
-    if (body_size && network::ShouldSniffContent(url, *head)) {
-      size_t bytes_to_sniff =
-          std::min(body_size, static_cast<size_t>(net::kMaxBytesToSniff));
-      const std::string hint = head->mime_type;
-      net::SniffMimeType(
-          base::StringPiece(body->front_as<const char>() + response_body_offset,
-                            bytes_to_sniff),
-          url, hint, net::ForceSniffFileUrlsForHtml::kDisabled,
-          &head->mime_type);
-      head->did_mime_sniff = true;
-    } else if (head->mime_type.empty()) {
-      head->mime_type.assign("text/plain");
-    }
+  if (head->mime_type.empty() && body_size) {
+    size_t bytes_to_sniff =
+        std::min(body_size, static_cast<size_t>(net::kMaxBytesToSniff));
+    net::SniffMimeType(
+        base::StringPiece(body->front_as<const char>() + response_body_offset,
+                          bytes_to_sniff),
+        create_loader_params_->request.url, "",
+        net::ForceSniffFileUrlsForHtml::kDisabled, &head->mime_type);
+    head->did_mime_sniff = true;
   }
   // TODO(caseq): we're cheating here a bit, raw_headers() have \0's
   // where real headers would have \r\n, but the sizes here
@@ -1075,7 +1067,7 @@ Response InterceptionJob::ProcessResponseOverride(
   base::OnceClosure continue_after_cookies_set;
   std::string location;
   if (head->headers->IsRedirect(&location)) {
-    GURL redirect_url = url.Resolve(location);
+    GURL redirect_url = create_loader_params_->request.url.Resolve(location);
     if (redirect_url.is_valid()) {
       continue_after_cookies_set =
           base::BindOnce(&InterceptionJob::ProcessRedirectByClient,

content/browser/devtools/protocol/network_handler.cc

@@ -15,6 +15,7 @@
 #include "base/containers/queue.h"
 #include "base/i18n/i18n_constants.h"
 #include "base/i18n/icu_string_conversions.h"
+#include "base/json/json_reader.h"
 #include "base/process/process_handle.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"

services/network/public/cpp/header_util.cc

@@ -5,10 +5,7 @@
 #include "services/network/public/cpp/header_util.h"
 
 #include "base/strings/string_util.h"
-#include "net/base/mime_sniffer.h"
 #include "net/http/http_request_headers.h"
-#include "services/network/public/mojom/url_response_head.mojom.h"
-#include "url/gurl.h"
 
 namespace network {
 
@@ -96,19 +93,4 @@ bool AreRequestHeadersSafe(const net::HttpRequestHeaders& request_headers) {
   return true;
 }
 
-bool ShouldSniffContent(const GURL& url,
-                        const mojom::URLResponseHead& response) {
-  std::string content_type_options;
-  if (response.headers) {
-    response.headers->GetNormalizedHeader("x-content-type-options",
-                                          &content_type_options);
-  }
-  bool sniffing_blocked =
-      base::LowerCaseEqualsASCII(content_type_options, "nosniff");
-  bool we_would_like_to_sniff =
-      net::ShouldSniffMimeType(url, response.mime_type);
-
-  return !sniffing_blocked && we_would_like_to_sniff;
-}
-
 }  // namespace network

services/network/public/cpp/header_util.h

@@ -8,15 +8,11 @@
 #include "base/component_export.h"
 #include "base/strings/string_piece.h"
 
-class GURL;
 namespace net {
 class HttpRequestHeaders;
 }  // namespace net
 
 namespace network {
-namespace mojom {
-class URLResponseHead;
-}  // namespace mojom
 
 // Checks if a single request header is safe to send.
 COMPONENT_EXPORT(NETWORK_CPP)
@@ -29,12 +25,6 @@ bool IsRequestHeaderSafe(const base::StringPiece& key,
 COMPONENT_EXPORT(NETWORK_CPP)
 bool AreRequestHeadersSafe(const net::HttpRequestHeaders& request_headers);
 
-// Checks whether mime type sniffing should be enabled, considering response
-// headers, current mime type and URL scheme.
-COMPONENT_EXPORT(NETWORK_CPP)
-bool ShouldSniffContent(const GURL& url,
-                        const mojom::URLResponseHead& response);
-
 }  // namespace network
 
 #endif  // SERVICES_NETWORK_PUBLIC_CPP_HEADER_UTIL_H_

services/network/url_loader.cc

@@ -380,6 +380,29 @@ mojom::HttpRawRequestResponseInfoPtr BuildRawRequestResponseInfo(
   return info;
 }
 
+bool ShouldSniffContent(net::URLRequest* url_request,
+                        const mojom::URLResponseHead& response) {
+  const std::string& mime_type = response.mime_type;
+
+  std::string content_type_options;
+  url_request->GetResponseHeaderByName("x-content-type-options",
+                                       &content_type_options);
+
+  bool sniffing_blocked =
+      base::LowerCaseEqualsASCII(content_type_options, "nosniff");
+  bool we_would_like_to_sniff =
+      net::ShouldSniffMimeType(url_request->url(), mime_type);
+
+  if (!sniffing_blocked && we_would_like_to_sniff) {
+    // We're going to look at the data before deciding what the content type
+    // is.  That means we need to delay sending the response started IPC.
+    VLOG(1) << "To buffer: " << url_request->url().spec();
+    return true;
+  }
+
+  return false;
+}
+
 // Concerning headers that consumers probably shouldn't be allowed to set.
 // Gathering numbers on these before adding them to kUnsafeHeaders.
 const struct {
@@ -1429,10 +1452,7 @@ void URLLoader::ContinueOnResponseStarted() {
     }
   }
   if ((options_ & mojom::kURLLoadOptionSniffMimeType)) {
-    if (ShouldSniffContent(url_request_->url(), *response_)) {
-      // We're going to look at the data before deciding what the content type
-      // is.  That means we need to delay sending the response started IPC.
-      VLOG(1) << "Will sniff content for mime type: " << url_request_->url();
+    if (ShouldSniffContent(url_request_.get(), *response_)) {
       is_more_mime_sniffing_needed_ = true;
     } else if (response_->mime_type.empty()) {
       // Ugg.  The server told us not to sniff the content but didn't give us