CSP: Fix DCHECK when processing a redirect.

CSP is not enforced while processing a redirect, so the DCHECK needs to
reflect that we are doing a redirect (not a response check) or that we
are not enforcing frame-ancestors in the browser process.

Bug: 1041711
Change-Id: Ib4872e0f8d96c944f14b5b6ed26b9b07008697dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2011744
Commit-Queue: Lucas Gadani <lfg@chromium.org>
Reviewed-by: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733605}

content/browser/frame_host/ancestor_throttle.cc

@@ -239,8 +239,8 @@ NavigationThrottle::ThrottleCheckResult AncestorThrottle::ProcessResponseImpl(
   }
 
   std::string header_value;
-  HeaderDisposition disposition =
-      ParseHeader(request->GetResponseHeaders(), &header_value);
+  HeaderDisposition disposition = ParseHeader(request->GetResponseHeaders(),
+                                              &header_value, is_response_check);
 
   switch (disposition) {
     case HeaderDisposition::CONFLICT:
@@ -363,7 +363,8 @@ void AncestorThrottle::ConsoleError(HeaderDisposition disposition) {
 
 AncestorThrottle::HeaderDisposition AncestorThrottle::ParseHeader(
     const net::HttpResponseHeaders* headers,
-    std::string* header_value) {
+    std::string* header_value,
+    bool is_response_check) {
   DCHECK(header_value);
   if (!headers)
     return HeaderDisposition::NONE;
@@ -406,8 +407,9 @@ AncestorThrottle::HeaderDisposition AncestorThrottle::ParseHeader(
   if (result != HeaderDisposition::NONE &&
       result != HeaderDisposition::ALLOWALL &&
       HeadersContainFrameAncestorsCSP(headers)) {
-    DCHECK(!base::FeatureList::IsEnabled(
-        network::features::kOutOfBlinkFrameAncestors));
+    DCHECK(!is_response_check ||
+           !base::FeatureList::IsEnabled(
+               network::features::kOutOfBlinkFrameAncestors));
     // TODO(mkwst): 'frame-ancestors' is currently handled in Blink. We should
     // handle it here instead. Until then, don't block the request, and let
     // Blink handle it. https://crbug.com/555418

content/browser/frame_host/ancestor_throttle.h

@@ -61,7 +61,8 @@ class CONTENT_EXPORT AncestorThrottle : public NavigationThrottle {
   // or INVALID, |header_value| will be populated with the value which caused
   // the parse error.
   HeaderDisposition ParseHeader(const net::HttpResponseHeaders* headers,
-                                std::string* header_value);
+                                std::string* header_value,
+                                bool is_response_check);
 
   DISALLOW_COPY_AND_ASSIGN(AncestorThrottle);
 };

content/browser/frame_host/ancestor_throttle_unittest.cc

@@ -89,7 +89,7 @@ TEST_F(AncestorThrottleTest, ParsingXFrameOptions) {
         GetAncestorHeaders(test.header, nullptr);
     std::string header_value;
     EXPECT_EQ(test.expected,
-              throttle.ParseHeader(headers.get(), &header_value));
+              throttle.ParseHeader(headers.get(), &header_value, true));
     EXPECT_EQ(test.value, header_value);
   }
 }
@@ -124,7 +124,7 @@ TEST_F(AncestorThrottleTest, ErrorsParsingXFrameOptions) {
         GetAncestorHeaders(test.header, nullptr);
     std::string header_value;
     EXPECT_EQ(test.expected,
-              throttle.ParseHeader(headers.get(), &header_value));
+              throttle.ParseHeader(headers.get(), &header_value, true));
     EXPECT_EQ(test.failure, header_value);
   }
 }
@@ -184,7 +184,7 @@ TEST_F(AncestorThrottleTest, IgnoreWhenFrameAncestorsPresent) {
         GetAncestorHeaders("DENY", test.csp);
     std::string header_value;
     EXPECT_EQ(test.expected,
-              throttle.ParseHeader(headers.get(), &header_value));
+              throttle.ParseHeader(headers.get(), &header_value, true));
     EXPECT_EQ("DENY", header_value);
   }
 }