Preserving Content-Type header from http request in OpenURL path.

chrome/browser/prerender/prerender_manager.cc

Index: chrome/browser/prerender/prerender_manager.cc
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index e4dfb19c7cef312817c55b56b2e27c23a1debc43..24b5b9a045eed4c9983fe2bc2c8361f3ce68919b 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -21,6 +21,7 @@
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/single_thread_task_runner.h"
+#include "base/strings/string_util.h"
 #include "base/sys_info.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
@@ -60,6 +61,7 @@
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/common/url_constants.h"
 #include "extensions/common/constants.h"
+#include "net/http/http_request_headers.h"
 #include "ui/gfx/geometry/rect.h"
 
 using content::BrowserThread;
@@ -78,6 +80,29 @@ const int kPeriodicCleanupIntervalMs = 1000;
 // Length of prerender history, for display in chrome://net-internals
 const int kHistoryLength = 100;
 
+// Check if |extra_headers| requested via chrome::NavigateParams::extra_headers
+// are the same as what the HTTP server saw when serving prerendered contents.
+// PrerenderContents::StartPrerendering doesn't specify any extra headers when
+// calling content::NavigationController::LoadURLWithParams, but in reality
+// Blink will always add an Upgrade-Insecure-Requests http request header, so
+// that HTTP request for prerendered contents always includes this header.
+// Because of this, it is okay to show prerendered contents even if
+// |extra_headers| contains "Upgrade-Insecure-Requests" header.
+bool AreExtraHeadersCompatibleWithPrerenderContents(
+    const std::string& extra_headers) {
+  net::HttpRequestHeaders parsed_headers;
+  parsed_headers.AddHeadersFromString(extra_headers);
+
+  net::HttpRequestHeaders::Iterator it(parsed_headers);
+  while (it.GetNext()) {
+    if (!base::EqualsCaseInsensitiveASCII(it.name(),
+                                          "upgrade-insecure-requests"))
+      return false;

[mmenke, 2016/10/11 20:46:33]

add braces.

[Łukasz Anforowicz, 2016/10/11 21:33:43]

Not applicable after applying your other suggestion.

+  }

[mmenke, 2016/10/11 20:46:33]

optional:  Could just do:

extra_headers.RemoveHeader("upgrade-insecure-requests");
return !extra_headers.IsEmpty();

(Doesn't work with multiple "upgrade-insecure-requests" headers, but I don't
think we care?)

[Łukasz Anforowicz, 2016/10/11 21:33:43]

Good point.  Done.

+
+  return true;
+}
+
 }  // namespace
 
 class PrerenderManager::OnCloseWebContentsDeleter
@@ -298,9 +323,14 @@ bool PrerenderManager::MaybeUsePrerenderedPage(const GURL& url,
   WebContents* web_contents = params->target_contents;
   DCHECK(!IsWebContentsPrerendering(web_contents, nullptr));
 
-  // Don't prerender if the navigation involves some special parameters.
-  if (params->uses_post || !params->extra_headers.empty())
+  // Don't prerender if the navigation involves some special parameters that
+  // are different from what was used by PrerenderContents::StartPrerendering
+  // (which always uses GET method and doesn't specify any extra headers when
+  // calling content::NavigationController::LoadURLWithParams).
+  if (params->uses_post ||
+      !AreExtraHeadersCompatibleWithPrerenderContents(params->extra_headers)) {
     return false;
+  }
 
   DeleteOldEntries();
   to_delete_prerenders_.clear();