Discard SSL certificates for non-committed entries to save memory.

content/browser/frame_host/navigation_controller_impl.cc

Index: content/browser/frame_host/navigation_controller_impl.cc
diff --git a/content/browser/frame_host/navigation_controller_impl.cc b/content/browser/frame_host/navigation_controller_impl.cc
index 5bde4bb4340d76cb67cc37f410824c5a814269d9..b7b9ea8a59c30bfc0da87c7efdcd0aee047fac09 100644
--- a/content/browser/frame_host/navigation_controller_impl.cc
+++ b/content/browser/frame_host/navigation_controller_impl.cc
@@ -559,6 +559,13 @@ int NavigationControllerImpl::GetIndexForOffset(int offset) const {
   return GetCurrentEntryIndex() + offset;
 }
 
+void NavigationControllerImpl::DiscardUnusedSSLCerts() {
+  for (size_t i = 0; i < entries_.size(); ++i) {
+    if (static_cast<int>(i) != last_committed_entry_index_)
+      entries_[i]->GetSSL().certificate = nullptr;
+  }
+}
+
 void NavigationControllerImpl::TakeScreenshot() {
   screenshot_manager_->TakeScreenshot();
 }
@@ -1272,6 +1279,7 @@ void NavigationControllerImpl::RendererDidNavigateToExistingPage(
   // If a transient entry was removed, the indices might have changed, so we
   // have to query the entry index again.
   last_committed_entry_index_ = GetIndexOfEntry(entry);
+  DiscardUnusedSSLCerts();
 }
 
 void NavigationControllerImpl::RendererDidNavigateToSamePage(
@@ -1397,6 +1405,7 @@ bool NavigationControllerImpl::RendererDidNavigateAutoSubframe(
       // case.  For newly created subframes, there was no pending entry.
       last_committed_entry_index_ = entry_index;
       DiscardNonCommittedEntriesInternal();
+      DiscardUnusedSSLCerts();
 
       // History navigations should send a commit notification.
       send_commit_notification = true;
@@ -1552,6 +1561,7 @@ void NavigationControllerImpl::CopyStateFromAndPrune(
 
   // Adjust indices such that the last entry and pending are at the end now.
   last_committed_entry_index_ = GetEntryCount() - 1;
+  DiscardUnusedSSLCerts();
 
   delegate_->SetHistoryOffsetAndLength(last_committed_entry_index_,
                                        GetEntryCount());
@@ -1762,6 +1772,7 @@ void NavigationControllerImpl::InsertOrReplaceEntry(
 
   entries_.push_back(std::move(entry));
   last_committed_entry_index_ = static_cast<int>(entries_.size()) - 1;
+  DiscardUnusedSSLCerts();
 }
 
 void NavigationControllerImpl::PruneOldestEntryIfFull() {
@@ -2069,6 +2080,7 @@ void NavigationControllerImpl::FinishRestore(int selected_index,
   ConfigureEntriesForRestore(&entries_, type);
 
   last_committed_entry_index_ = selected_index;
+  DiscardUnusedSSLCerts();
 }
 
 void NavigationControllerImpl::DiscardNonCommittedEntriesInternal() {