Add DumpWithoutCrashing to CaptivePortalTabHelper

Add several calls to DumpWithoutCrashing to CaptivePortalTabHelper to
try to understand what is causing crbug.com/704892.

BUG=704892

Review-Url: https://codereview.chromium.org/2796573005
Cr-Commit-Position: refs/heads/master@{#462443}

chrome/browser/captive_portal/captive_portal_tab_helper.cc

@@ -5,6 +5,7 @@
 #include "chrome/browser/captive_portal/captive_portal_tab_helper.h"
 
 #include "base/bind.h"
+#include "base/debug/dump_without_crashing.h"
 #include "chrome/browser/captive_portal/captive_portal_login_detector.h"
 #include "chrome/browser/captive_portal/captive_portal_service_factory.h"
 #include "chrome/browser/captive_portal/captive_portal_tab_reloader.h"
@@ -60,6 +61,11 @@ void CaptivePortalTabHelper::DidStartNavigation(
   if (!navigation_handle->IsInMainFrame())
     return;
 
+  // TODO(clamy): Remove this when we understand the root cause behind
+  // crbug.com/704892.
+  if (navigation_handle == navigation_handle_)
+    base::debug::DumpWithoutCrashing();
+
   // Always track the latest navigation. If a navigation was already tracked,
   // and it committed (either the navigation proper or an error page), it is
   // safe to start tracking the new navigation. Otherwise simulate an abort
@@ -86,8 +92,13 @@ void CaptivePortalTabHelper::DidRedirectNavigation(
 void CaptivePortalTabHelper::DidFinishNavigation(
     content::NavigationHandle* navigation_handle) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  if (!navigation_handle->IsInMainFrame())
+  if (!navigation_handle->IsInMainFrame()) {
+    if (navigation_handle == navigation_handle_)
+      // TODO(clamy): Remove this when we understand the root cause behind
+      // crbug.com/704892.
+      base::debug::DumpWithoutCrashing();
     return;
+  }
 
   if (navigation_handle_ != navigation_handle) {
     // Another navigation is being tracked, so there is no need to update the
@@ -99,6 +110,11 @@ void CaptivePortalTabHelper::DidFinishNavigation(
     DidStartNavigation(navigation_handle);
   }
 
+  // TODO(clamy): Remove this when we understand the root cause behind
+  // crbug.com/704892.
+  if (navigation_handle != navigation_handle_)
+    base::debug::DumpWithoutCrashing();
+
   if (navigation_handle->HasCommitted()) {
     tab_reloader_->OnLoadCommitted(navigation_handle->GetNetErrorCode());
   } else {