Last_n: Do not save a snapshot of a closing tab.

chrome/browser/android/offline_pages/recent_tab_helper.cc

Index: chrome/browser/android/offline_pages/recent_tab_helper.cc
diff --git a/chrome/browser/android/offline_pages/recent_tab_helper.cc b/chrome/browser/android/offline_pages/recent_tab_helper.cc
index a2019a31586b8f1c5fda136110dfc058743c1c1f..3e9bc62f549c6bf009ede639f2cfbd7faea9c02d 100644
--- a/chrome/browser/android/offline_pages/recent_tab_helper.cc
+++ b/chrome/browser/android/offline_pages/recent_tab_helper.cc
@@ -247,10 +247,16 @@ void RecentTabHelper::WasHidden() {
   if (!IsOffliningRecentPagesEnabled())
     return;
 
-  // Return immediately if last_n is not listening to tab hidden events or if a
-  // last_n snapshot is currently being saved.
-  if (!last_n_listen_to_tab_hidden_ || last_n_ongoing_snapshot_info_)
+  // Return immediately if last_n is not listening to tab hidden events, if a
+  // last_n snapshot is currently being saved or if the tab is closing.
+  if (!last_n_listen_to_tab_hidden_ || last_n_ongoing_snapshot_info_ ||
+      tab_is_closing) {
+    DVLOG(1) << "Will not snapshot for last_n (reasons: "
+             << !last_n_listen_to_tab_hidden_ << ", "
+             << !!last_n_ongoing_snapshot_info_ << ", " << tab_is_closing
+             << ") for: " << web_contents()->GetLastCommittedURL().spec();
     return;
+  }
 
   // Do not save if page quality is too low.
   // Note: we assume page quality for a page can only increase.
@@ -269,6 +275,19 @@ void RecentTabHelper::WasHidden() {
                  last_n_ongoing_snapshot_info_.get()));
 }
 
+void RecentTabHelper::WasShown() {
+  // If the tab was closing and is now being shown, the closure was reverted.
+  DVLOG_IF(0, tab_is_closing) << "Tab is not closing anymore: "
+                              << web_contents()->GetLastCommittedURL().spec();
+  tab_is_closing = false;
+}
+
+void RecentTabHelper::WillCloseTab() {
+  DVLOG(1) << "Tab is now closing: "
+           << web_contents()->GetLastCommittedURL().spec();
+  tab_is_closing = true;
+}
+
 // TODO(carlosk): rename this to RequestSnapshot and make it return a bool
 // representing the acceptance of the snapshot request.
 void RecentTabHelper::StartSnapshot() {