Call WillStartRequestForTesting in TestRenderFrameHost

This CL calls WillStartRequest on the current NavigationHandle when a
navigation is starting. This mimics the SimulateRedirect call, and enables
NavigationThrottles which override WillStartRequest to be unit testable
using the content unit test framework.

Note: like SimulateRedirect, there is no current support for the throttles
actually cancelling / deferring the navigation.

BUG=627501

Review-Url: https://codereview.chromium.org/2157153003
Cr-Commit-Position: refs/heads/master@{#407150}

chrome/browser/chrome_content_browser_client.cc

@@ -2964,7 +2964,8 @@ ChromeContentBrowserClient::CreateThrottlesForNavigation(
     // Add interstitial page while merge session process (cookie reconstruction
     // from OAuth2 refresh token in ChromeOS login) is still in progress while
     // we are attempting to load a google property.
-    if (!merge_session_throttling_utils::AreAllSessionMergedAlready() &&
+    if (merge_session_throttling_utils::ShouldAttachNavigationThrottle() &&
+        !merge_session_throttling_utils::AreAllSessionMergedAlready() &&
         handle->GetURL().SchemeIsHTTPOrHTTPS()) {
       throttles.push_back(MergeSessionNavigationThrottle::Create(handle));
     }

chrome/browser/chromeos/login/signin/merge_session_throttling_utils.cc

@@ -63,6 +63,10 @@ base::AtomicRefCount g_all_profiles_restored_ = 0;
 
 }  // namespace
 
+bool ShouldAttachNavigationThrottle() {
+  return user_manager::UserManager::IsInitialized();
+}
+
 bool AreAllSessionMergedAlready() {
   return !base::AtomicRefCountIsZero(&g_all_profiles_restored_);
 }

chrome/browser/chromeos/login/signin/merge_session_throttling_utils.h

@@ -25,6 +25,11 @@ namespace merge_session_throttling_utils {
 // page load.
 using CompletionCallback = base::Closure;
 
+// Policy for when it is valid to attach a MergeSessionNavigationThrottle.
+// Namely, this will be false for unit tests, where the UserManager is not
+// initialized.
+bool ShouldAttachNavigationThrottle();
+
 // Checks if session is already merged. This is safe to call on all threads.
 bool AreAllSessionMergedAlready();
 

content/test/test_render_frame_host.cc

@@ -14,6 +14,7 @@
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/frame_messages.h"
 #include "content/common/frame_owner_properties.h"
+#include "content/public/browser/navigation_throttle.h"
 #include "content/public/browser/stream_handle.h"
 #include "content/public/common/browser_side_navigation_policy.h"
 #include "content/public/common/url_constants.h"
@@ -106,6 +107,7 @@ void TestRenderFrameHost::SimulateNavigationStart(const GURL& url) {
 
   OnDidStartLoading(true);
   OnDidStartProvisionalLoad(url, base::TimeTicks::Now());
+  SimulateWillStartRequest(ui::PAGE_TRANSITION_LINK);
 }
 
 void TestRenderFrameHost::SimulateRedirect(const GURL& new_url) {
@@ -290,6 +292,7 @@ void TestRenderFrameHost::SendNavigateWithParameters(
   // so we keep a copy of it to use below.
   GURL url_copy(url);
   OnDidStartProvisionalLoad(url_copy, base::TimeTicks::Now());
+  SimulateWillStartRequest(transition);
 
   FrameHostMsg_DidCommitProvisionalLoad_Params params;
   params.page_id = page_id;
@@ -440,4 +443,13 @@ int32_t TestRenderFrameHost::ComputeNextPageID() {
   return page_id;
 }
 
+void TestRenderFrameHost::SimulateWillStartRequest(
+    ui::PageTransition transition) {
+  if (!navigation_handle())
+    return;
+  navigation_handle()->CallWillStartRequestForTesting(
+      false /* is_post */, Referrer(GURL(), blink::WebReferrerPolicyDefault),
+      true /* user_gesture */, transition, false /* is_external_protocol */);
+}
+
 }  // namespace content

content/test/test_render_frame_host.h

@@ -149,6 +149,8 @@ class TestRenderFrameHost : public RenderFrameHostImpl,
   // Computes the page ID for a pending navigation in this RenderFrameHost;
   int32_t ComputeNextPageID();
 
+  void SimulateWillStartRequest(ui::PageTransition transition);
+
   TestRenderFrameHostCreationObserver child_creation_observer_;
 
   std::string contents_mime_type_;