Preserving extra http request headers in OpenURL navigation path [relanding].

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 d455df42fed10bb70d3dd1acb72d50095f7c4373..5aec206c98c4fbf341f515b23a9a1d5f75d7a6e8 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 +80,22 @@ 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);
+  parsed_headers.RemoveHeader("upgrade-insecure-requests");
+  return parsed_headers.IsEmpty();
+}
+
 }  // namespace
 
 class PrerenderManager::OnCloseWebContentsDeleter
@@ -299,9 +317,14 @@ 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();