Revert the merge of CrossSiteResourceHandler and NavigationResourceThrottle.

content/browser/loader/cross_site_resource_handler.cc

Index: content/browser/loader/cross_site_resource_handler.cc
diff --git a/content/browser/loader/cross_site_resource_handler.cc b/content/browser/loader/cross_site_resource_handler.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ecffa2095fcb199ad1d9fc2b639fb64f6677fa39
--- /dev/null
+++ b/content/browser/loader/cross_site_resource_handler.cc
@@ -0,0 +1,388 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/loader/cross_site_resource_handler.h"
+
+#include <string>
+#include <utility>
+
+#include "base/bind.h"
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "content/browser/appcache/appcache_interceptor.h"
+#include "content/browser/child_process_security_policy_impl.h"
+#include "content/browser/frame_host/cross_site_transferring_request.h"
+#include "content/browser/frame_host/render_frame_host_impl.h"
+#include "content/browser/loader/resource_dispatcher_host_impl.h"
+#include "content/browser/loader/resource_request_info_impl.h"
+#include "content/browser/site_instance_impl.h"
+#include "content/browser/web_contents/web_contents_impl.h"
+#include "content/common/site_isolation_policy.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/content_browser_client.h"
+#include "content/public/browser/global_request_id.h"
+#include "content/public/browser/resource_controller.h"
+#include "content/public/browser/site_instance.h"
+#include "content/public/common/content_switches.h"
+#include "content/public/common/resource_response.h"
+#include "content/public/common/url_constants.h"
+#include "net/http/http_response_headers.h"
+#include "net/url_request/url_request.h"
+
+namespace content {
+
+namespace {
+
+bool leak_requests_for_testing_ = false;
+
+// The parameters to OnCrossSiteResponseHelper exceed the number of arguments
+// base::Bind supports.
+struct CrossSiteResponseParams {
+  CrossSiteResponseParams(
+      int render_frame_id,
+      const GlobalRequestID& global_request_id,
+      const std::vector<GURL>& transfer_url_chain,
+      const Referrer& referrer,
+      ui::PageTransition page_transition,
+      bool should_replace_current_entry)
+      : render_frame_id(render_frame_id),
+        global_request_id(global_request_id),
+        transfer_url_chain(transfer_url_chain),
+        referrer(referrer),
+        page_transition(page_transition),
+        should_replace_current_entry(should_replace_current_entry) {
+  }
+
+  int render_frame_id;
+  GlobalRequestID global_request_id;
+  std::vector<GURL> transfer_url_chain;
+  Referrer referrer;
+  ui::PageTransition page_transition;
+  bool should_replace_current_entry;
+};
+
+void OnCrossSiteResponseHelper(const CrossSiteResponseParams& params) {
+  std::unique_ptr<CrossSiteTransferringRequest> cross_site_transferring_request(
+      new CrossSiteTransferringRequest(params.global_request_id));
+
+  RenderFrameHostImpl* rfh =
+      RenderFrameHostImpl::FromID(params.global_request_id.child_id,
+                                  params.render_frame_id);
+  if (rfh && rfh->is_active()) {
+    if (rfh->GetParent()) {
+      // We should only swap processes for subframes in --site-per-process mode.
+      // CrossSiteResourceHandler is not installed on subframe requests in
+      // default Chrome.
+      CHECK(SiteIsolationPolicy::AreCrossProcessFramesPossible());
+    }
+    rfh->OnCrossSiteResponse(
+        params.global_request_id, std::move(cross_site_transferring_request),
+        params.transfer_url_chain, params.referrer, params.page_transition,
+        params.should_replace_current_entry);
+  } else if (leak_requests_for_testing_) {
+    // Some unit tests expect requests to be leaked in this case, so they can
+    // pass them along manually.
+    cross_site_transferring_request->ReleaseRequest();
+  }
+}
+
+// Returns whether a transfer is needed by doing a check on the UI thread.
+CrossSiteResourceHandler::NavigationDecision
+CheckNavigationPolicyOnUI(GURL real_url, int process_id, int render_frame_id) {
+  CHECK(SiteIsolationPolicy::AreCrossProcessFramesPossible());
+  RenderFrameHostImpl* rfh =
+      RenderFrameHostImpl::FromID(process_id, render_frame_id);
+
+  // Without a valid RFH against which to check, we must cancel the request,
+  // to prevent the resource at |url| from being delivered to a potentially
+  // unsuitable renderer process.
+  if (!rfh || !rfh->is_active())
+    return CrossSiteResourceHandler::NavigationDecision::CANCEL_REQUEST;
+
+  RenderFrameHostManager* manager = rfh->frame_tree_node()->render_manager();
+  if (manager->IsRendererTransferNeededForNavigation(rfh, real_url))
+    return CrossSiteResourceHandler::NavigationDecision::TRANSFER_REQUIRED;
+  else
+    return CrossSiteResourceHandler::NavigationDecision::USE_EXISTING_RENDERER;
+}
+
+}  // namespace
+
+CrossSiteResourceHandler::CrossSiteResourceHandler(
+    std::unique_ptr<ResourceHandler> next_handler,
+    net::URLRequest* request)
+    : LayeredResourceHandler(request, std::move(next_handler)),
+      has_started_response_(false),
+      in_cross_site_transition_(false),
+      completed_during_transition_(false),
+      did_defer_(false),
+      weak_ptr_factory_(this) {}
+
+CrossSiteResourceHandler::~CrossSiteResourceHandler() {
+  // Cleanup back-pointer stored on the request info.
+  GetRequestInfo()->set_cross_site_handler(NULL);
+}
+
+bool CrossSiteResourceHandler::OnRequestRedirected(
+    const net::RedirectInfo& redirect_info,
+    ResourceResponse* response,
+    bool* defer) {
+  // We should not have started the transition before being redirected.
+  DCHECK(!in_cross_site_transition_);
+  return next_handler_->OnRequestRedirected(redirect_info, response, defer);
+}
+
+bool CrossSiteResourceHandler::OnResponseStarted(
+    ResourceResponse* response,
+    bool* defer) {
+  response_ = response;
+  has_started_response_ = true;
+
+  // Store this handler on the ExtraRequestInfo, so that RDH can call our
+  // ResumeResponse method when we are ready to resume.
+  ResourceRequestInfoImpl* info = GetRequestInfo();
+  info->set_cross_site_handler(this);
+
+  return OnNormalResponseStarted(response, defer);
+}
+
+bool CrossSiteResourceHandler::OnNormalResponseStarted(
+    ResourceResponse* response,
+    bool* defer) {
+  // At this point, we know that the response is safe to send back to the
+  // renderer: it is not a download, and it has passed the SSL and safe
+  // browsing checks.
+  // We should not have already started the transition before now.
+  DCHECK(!in_cross_site_transition_);
+
+  ResourceRequestInfoImpl* info = GetRequestInfo();
+
+  // The content embedder can decide that a transfer to a different process is
+  // required for this URL.  If so, pause the response now.  Other cross process
+  // navigations can proceed immediately, since we run the unload handler at
+  // commit time.  Note that a process swap may no longer be necessary if we
+  // transferred back into the original process due to a redirect.
+  bool definitely_transfer =
+      GetContentClient()->browser()->ShouldSwapProcessesForRedirect(
+          info->GetContext(), request()->original_url(), request()->url());
+
+  // If this is a download, just pass the response through without doing a
+  // cross-site check.  The renderer will see it is a download and abort the
+  // request.
+  //
+  // Similarly, HTTP 204 (No Content) responses leave us showing the previous
+  // page.  We should allow the navigation to finish without running the unload
+  // handler or swapping in the pending RenderFrameHost.
+  //
+  // In both cases, any pending RenderFrameHost (if one was created for this
+  // navigation) will stick around until the next cross-site navigation, since
+  // we are unable to tell when to destroy it.
+  // See RenderFrameHostManager::RendererAbortedProvisionalLoad.
+  //
+  // TODO(davidben): Unify IsDownload() and is_stream(). Several places need to
+  // check for both and remembering about streams is error-prone.
+  if (info->IsDownload() || info->is_stream() ||
+      (response->head.headers.get() &&
+       response->head.headers->response_code() == 204)) {
+    return next_handler_->OnResponseStarted(response, defer);
+  }
+
+  if (definitely_transfer) {
+    // Now that we know a transfer is needed and we have something to commit, we
+    // pause to let the UI thread set up the transfer.
+    StartCrossSiteTransition(response);
+
+    // Defer loading until after the new renderer process has issued a
+    // corresponding request.
+    *defer = true;
+    OnDidDefer();
+    return true;
+  }
+
+  // In the site-per-process model, we may also decide (independently from the
+  // content embedder's ShouldSwapProcessesForRedirect decision above) that a
+  // process transfer is needed.  For that we need to consult the navigation
+  // policy on the UI thread, so pause the response.  Process transfers are
+  // skipped for WebUI processes for now, since e.g. chrome://settings has
+  // multiple "cross-site" chrome:// frames, and that doesn't yet work cross-
+  // process.
+  if (SiteIsolationPolicy::AreCrossProcessFramesPossible() &&
+      !ChildProcessSecurityPolicyImpl::GetInstance()->HasWebUIBindings(
+          info->GetChildID())) {
+    return DeferForNavigationPolicyCheck(info, response, defer);
+  }
+
+  // No deferral needed. Pass the response through.
+  return next_handler_->OnResponseStarted(response, defer);
+}
+
+void CrossSiteResourceHandler::ResumeOrTransfer(NavigationDecision decision) {
+  switch (decision) {
+    case NavigationDecision::CANCEL_REQUEST:
+      // TODO(nick): What kind of cleanup do we need here?
+      controller()->Cancel();
+      break;
+    case NavigationDecision::USE_EXISTING_RENDERER:
+      ResumeResponse();
+      break;
+    case NavigationDecision::TRANSFER_REQUIRED:
+      StartCrossSiteTransition(response_.get());
+      break;
+  }
+}
+
+bool CrossSiteResourceHandler::OnReadCompleted(int bytes_read, bool* defer) {
+  CHECK(!in_cross_site_transition_);
+  return next_handler_->OnReadCompleted(bytes_read, defer);
+}
+
+void CrossSiteResourceHandler::OnResponseCompleted(
+    const net::URLRequestStatus& status,
+    bool* defer) {
+  if (!in_cross_site_transition_) {
+    // If we're not transferring, then we should pass this through.
+    next_handler_->OnResponseCompleted(status, defer);
+    return;
+  }
+
+  // We have to buffer the call until after the transition completes.
+  completed_during_transition_ = true;
+  completed_status_ = status;
+
+  // Defer to tell RDH not to notify the world or clean up the pending request.
+  // We will do so in ResumeResponse.
+  *defer = true;
+  OnDidDefer();
+}
+
+// We can now send the response to the new renderer, which will cause
+// WebContentsImpl to swap in the new renderer and destroy the old one.
+void CrossSiteResourceHandler::ResumeResponse() {
+  TRACE_EVENT_ASYNC_END0(
+      "navigation", "CrossSiteResourceHandler transition", this);
+  DCHECK(request());
+  in_cross_site_transition_ = false;
+  ResourceRequestInfoImpl* info = GetRequestInfo();
+
+  if (has_started_response_) {
+    // Send OnResponseStarted to the new renderer.
+    DCHECK(response_.get());
+    bool defer = false;
+    if (!next_handler_->OnResponseStarted(response_.get(), &defer)) {
+      controller()->Cancel();
+    } else if (!defer) {
+      // Unpause the request to resume reading.  Any further reads will be
+      // directed toward the new renderer.
+      ResumeIfDeferred();
+    }
+  }
+
+  // Remove ourselves from the ExtraRequestInfo.
+  info->set_cross_site_handler(NULL);
+
+  // If the response completed during the transition, notify the next
+  // event handler.
+  if (completed_during_transition_) {
+    bool defer = false;
+    next_handler_->OnResponseCompleted(completed_status_,
+                                       &defer);
+    if (!defer)
+      ResumeIfDeferred();
+  }
+}
+
+// static
+void CrossSiteResourceHandler::SetLeakRequestsForTesting(
+    bool leak_requests_for_testing) {
+  leak_requests_for_testing_ = leak_requests_for_testing;
+}
+
+// Prepare to transfer the response to a new RenderFrameHost.
+void CrossSiteResourceHandler::StartCrossSiteTransition(
+    ResourceResponse* response) {
+  TRACE_EVENT_ASYNC_BEGIN0(
+      "navigation", "CrossSiteResourceHandler transition", this);
+  in_cross_site_transition_ = true;
+  response_ = response;
+
+  // Store this handler on the ExtraRequestInfo, so that RDH can call our
+  // ResumeResponse method when we are ready to resume.
+  ResourceRequestInfoImpl* info = GetRequestInfo();
+  info->set_cross_site_handler(this);
+
+  GlobalRequestID global_id(info->GetChildID(), info->GetRequestID());
+
+  // Tell the contents responsible for this request that a cross-site response
+  // is starting, so that it can tell its old renderer to run its onunload
+  // handler now.  We will wait until the unload is finished and (if a transfer
+  // is needed) for the new renderer's request to arrive.
+  // The |transfer_url_chain| contains any redirect URLs that have already
+  // occurred, plus the destination URL at the end.
+  std::vector<GURL> transfer_url_chain;
+  Referrer referrer;
+  int render_frame_id = info->GetRenderFrameID();
+  transfer_url_chain = request()->url_chain();
+  referrer = Referrer(GURL(request()->referrer()), info->GetReferrerPolicy());
+  ResourceDispatcherHostImpl::Get()->MarkAsTransferredNavigation(global_id,
+                                                                 response_);
+
+  BrowserThread::PostTask(
+      BrowserThread::UI,
+      FROM_HERE,
+      base::Bind(
+          &OnCrossSiteResponseHelper,
+          CrossSiteResponseParams(render_frame_id,
+                                  global_id,
+                                  transfer_url_chain,
+                                  referrer,
+                                  info->GetPageTransition(),
+                                  info->should_replace_current_entry())));
+}
+
+bool CrossSiteResourceHandler::DeferForNavigationPolicyCheck(
+    ResourceRequestInfoImpl* info,
+    ResourceResponse* response,
+    bool* defer) {
+  // Store the response_ object internally, since the navigation is deferred
+  // regardless of whether it will be a transfer or not.
+  response_ = response;
+
+  // Always defer the navigation to the UI thread to make a policy decision.
+  // It will send the result back to the IO thread to either resume or
+  // transfer it to a new renderer.
+  // TODO(nasko): If the UI thread result is that transfer is required, the
+  // IO thread will defer to the UI thread again through
+  // StartCrossSiteTransition. This is unnecessary and the policy check on the
+  // UI thread should be refactored to avoid the extra hop.
+  BrowserThread::PostTaskAndReplyWithResult(
+      BrowserThread::UI,
+      FROM_HERE,
+      base::Bind(&CheckNavigationPolicyOnUI,
+                 request()->url(),
+                 info->GetChildID(),
+                 info->GetRenderFrameID()),
+      base::Bind(&CrossSiteResourceHandler::ResumeOrTransfer,
+                 weak_ptr_factory_.GetWeakPtr()));
+
+  // Defer loading until it is known whether the navigation will transfer
+  // to a new process or continue in the existing one.
+  *defer = true;
+  OnDidDefer();
+  return true;
+}
+
+void CrossSiteResourceHandler::ResumeIfDeferred() {
+  if (did_defer_) {
+    request()->LogUnblocked();
+    did_defer_ = false;
+    controller()->Resume();
+  }
+}
+
+void CrossSiteResourceHandler::OnDidDefer() {
+  did_defer_ = true;
+  request()->LogBlockedBy("CrossSiteResourceHandler");
+}
+
+}  // namespace content