OOPIF: Support session restore by combining/splitting frame PageStates.

In OOPIF-enabled modes, each FrameNavigationEntry has a per-frame
PageState object.  The states for each frame in the tree need to be
combined into a single PageState for GetPageState, and a single
PageState needs to be split into individual FrameNavigationEntries for
SetPageState.

Because GetPageState is const and returns a const ref, we need to
cache the combined PageState each time it could change.

BUG=545219
TEST=Close and restore a tab or session with OOPIFs.

Review URL: https://codereview.chromium.org/1496483002

Cr-Commit-Position: refs/heads/master@{#363025}

content/browser/frame_host/navigation_controller_impl.cc

@@ -1847,11 +1847,12 @@ void NavigationControllerImpl::FindFramesToNavigate(
     return;
 
   // Schedule a load in this frame if the new item isn't for the same item
-  // sequence number in the same SiteInstance.
-  // TODO(creis): Handle null SiteInstances during session restore.
+  // sequence number in the same SiteInstance. Newly restored items may not have
+  // a SiteInstance yet, in which case it will be assigned on first commit.
   if (!old_item ||
       new_item->item_sequence_number() != old_item->item_sequence_number() ||
-      new_item->site_instance() != old_item->site_instance()) {
+      (new_item->site_instance() != nullptr &&
+       new_item->site_instance() != old_item->site_instance())) {
     if (old_item &&
         new_item->document_sequence_number() ==
             old_item->document_sequence_number()) {

content/browser/frame_host/navigation_controller_impl_browsertest.cc

@@ -2320,7 +2320,7 @@ IN_PROC_BROWSER_TEST_F(NavigationControllerBrowserTest,
   ASSERT_EQ(1U, entry1->root_node()->children.size());
   EXPECT_EQ(data_url, entry1->root_node()->children[0]->frame_entry->url());
 
-  // 2. Navigate the iframe cross-site to a page with a nested iframe.
+  // 2. Navigate the iframe cross-site.
   GURL frame_url_b(embedded_test_server()->GetURL(
       "b.com", "/navigation_controller/simple_page_1.html"));
   {
@@ -2378,6 +2378,144 @@ IN_PROC_BROWSER_TEST_F(NavigationControllerBrowserTest,
   EXPECT_EQ(data_url, entry2->root_node()->children[1]->frame_entry->url());
 }
 
+// Verify that subframes can be restored in a new NavigationController using the
+// PageState of an existing NavigationEntry.
+IN_PROC_BROWSER_TEST_F(NavigationControllerBrowserTest,
+                       FrameNavigationEntry_RestoreViaPageState) {
+  // 1. Start on a page with a data URL iframe.
+  GURL main_url_a(embedded_test_server()->GetURL(
+      "a.com", "/navigation_controller/page_with_data_iframe.html"));
+  GURL data_url("data:text/html,Subframe");
+  NavigateToURL(shell(), main_url_a);
+  const NavigationControllerImpl& controller =
+      static_cast<const NavigationControllerImpl&>(
+          shell()->web_contents()->GetController());
+  FrameTreeNode* root = static_cast<WebContentsImpl*>(shell()->web_contents())
+                            ->GetFrameTree()
+                            ->root();
+  ASSERT_EQ(1U, root->child_count());
+  ASSERT_EQ(0U, root->child_at(0)->child_count());
+  EXPECT_EQ(main_url_a, root->current_url());
+  EXPECT_EQ(data_url, root->child_at(0)->current_url());
+
+  EXPECT_EQ(1, controller.GetEntryCount());
+  EXPECT_EQ(0, controller.GetLastCommittedEntryIndex());
+  NavigationEntryImpl* entry1 = controller.GetLastCommittedEntry();
+
+  // Verify subframe entries if they're enabled (e.g. in --site-per-process).
+  if (SiteIsolationPolicy::UseSubframeNavigationEntries()) {
+    // The entry should have a FrameNavigationEntry for the data subframe.
+    ASSERT_EQ(1U, entry1->root_node()->children.size());
+    EXPECT_EQ(data_url, entry1->root_node()->children[0]->frame_entry->url());
+  } else {
+    // There are no subframe FrameNavigationEntries by default.
+    EXPECT_EQ(0U, entry1->root_node()->children.size());
+  }
+
+  // 2. Navigate the iframe cross-site.
+  GURL frame_url_b(embedded_test_server()->GetURL(
+      "b.com", "/navigation_controller/simple_page_1.html"));
+  {
+    FrameNavigateParamsCapturer capturer(root->child_at(0));
+    NavigateFrameToURL(root->child_at(0), frame_url_b);
+    capturer.Wait();
+  }
+  ASSERT_EQ(1U, root->child_count());
+  EXPECT_EQ(main_url_a, root->current_url());
+  EXPECT_EQ(frame_url_b, root->child_at(0)->current_url());
+
+  EXPECT_EQ(2, controller.GetEntryCount());
+  EXPECT_EQ(1, controller.GetLastCommittedEntryIndex());
+  NavigationEntryImpl* entry2 = controller.GetLastCommittedEntry();
+
+  // Verify subframe entries if they're enabled (e.g. in --site-per-process).
+  if (SiteIsolationPolicy::UseSubframeNavigationEntries()) {
+    // The entry should have a FrameNavigationEntry for the b.com subframe.
+    ASSERT_EQ(1U, entry2->root_node()->children.size());
+    EXPECT_EQ(frame_url_b,
+              entry2->root_node()->children[0]->frame_entry->url());
+  } else {
+    // There are no subframe FrameNavigationEntries by default.
+    EXPECT_EQ(0U, entry2->root_node()->children.size());
+  }
+
+  // 3. Navigate main frame cross-site, destroying the frames.
+  GURL main_url_c(embedded_test_server()->GetURL(
+      "c.com", "/navigation_controller/simple_page_2.html"));
+  NavigateToURL(shell(), main_url_c);
+  ASSERT_EQ(0U, root->child_count());
+  EXPECT_EQ(main_url_c, root->current_url());
+
+  EXPECT_EQ(3, controller.GetEntryCount());
+  EXPECT_EQ(2, controller.GetLastCommittedEntryIndex());
+  NavigationEntryImpl* entry3 = controller.GetLastCommittedEntry();
+  EXPECT_EQ(0U, entry3->root_node()->children.size());
+
+  // 4. Create a NavigationEntry with the same PageState as |entry2| and verify
+  // it has the same FrameNavigationEntry structure.
+  scoped_ptr<NavigationEntryImpl> restored_entry =
+      NavigationEntryImpl::FromNavigationEntry(
+          NavigationControllerImpl::CreateNavigationEntry(
+              main_url_a, Referrer(), ui::PAGE_TRANSITION_RELOAD, false,
+              std::string(), controller.GetBrowserContext()));
+  restored_entry->SetPageID(0);
+  EXPECT_EQ(0U, restored_entry->root_node()->children.size());
+  restored_entry->SetPageState(entry2->GetPageState());
+
+  // Verify subframe entries if they're enabled (e.g. in --site-per-process).
+  if (SiteIsolationPolicy::UseSubframeNavigationEntries()) {
+    // The entry should have a FrameNavigationEntry for the b.com subframe.
+    EXPECT_EQ(main_url_a, restored_entry->root_node()->frame_entry->url());
+    ASSERT_EQ(1U, restored_entry->root_node()->children.size());
+    EXPECT_EQ(frame_url_b,
+              restored_entry->root_node()->children[0]->frame_entry->url());
+  } else {
+    // There are no subframe FrameNavigationEntries by default.
+    EXPECT_EQ(0U, restored_entry->root_node()->children.size());
+  }
+
+  // 5. Restore the new entry in a new tab and verify the correct URLs load.
+  std::vector<scoped_ptr<NavigationEntry>> entries;
+  entries.push_back(restored_entry.Pass());
+  Shell* new_shell = Shell::CreateNewWindow(
+      controller.GetBrowserContext(), GURL::EmptyGURL(), nullptr, gfx::Size());
+  FrameTreeNode* new_root =
+      static_cast<WebContentsImpl*>(new_shell->web_contents())
+          ->GetFrameTree()
+          ->root();
+  NavigationControllerImpl& new_controller =
+      static_cast<NavigationControllerImpl&>(
+          new_shell->web_contents()->GetController());
+  new_controller.Restore(
+      entries.size() - 1,
+      NavigationController::RESTORE_LAST_SESSION_EXITED_CLEANLY, &entries);
+  ASSERT_EQ(0u, entries.size());
+  {
+    TestNavigationObserver restore_observer(new_shell->web_contents());
+    new_controller.LoadIfNecessary();
+    restore_observer.Wait();
+  }
+  ASSERT_EQ(1U, new_root->child_count());
+  EXPECT_EQ(main_url_a, new_root->current_url());
+  EXPECT_EQ(frame_url_b, new_root->child_at(0)->current_url());
+
+  EXPECT_EQ(1, new_controller.GetEntryCount());
+  EXPECT_EQ(0, new_controller.GetLastCommittedEntryIndex());
+  NavigationEntryImpl* new_entry = new_controller.GetLastCommittedEntry();
+
+  // Verify subframe entries if they're enabled (e.g. in --site-per-process).
+  if (SiteIsolationPolicy::UseSubframeNavigationEntries()) {
+    // The entry should have a FrameNavigationEntry for the b.com subframe.
+    EXPECT_EQ(main_url_a, new_entry->root_node()->frame_entry->url());
+    ASSERT_EQ(1U, new_entry->root_node()->children.size());
+    EXPECT_EQ(frame_url_b,
+              new_entry->root_node()->children[0]->frame_entry->url());
+  } else {
+    // There are no subframe FrameNavigationEntries by default.
+    EXPECT_EQ(0U, new_entry->root_node()->children.size());
+  }
+}
+
 // Verifies that the |frame_unique_name| is set to the correct frame, so that we
 // can match subframe FrameNavigationEntries to newly created frames after
 // back/forward and restore.

content/browser/frame_host/navigation_entry_impl.cc

@@ -17,14 +17,72 @@
 #include "content/public/common/url_constants.h"
 #include "ui/gfx/text_elider.h"
 
+using base::UTF16ToUTF8;
+
+namespace content {
+
+namespace {
+
 // Use this to get a new unique ID for a NavigationEntry during construction.
 // The returned ID is guaranteed to be nonzero (which is the "no ID" indicator).
-static int GetUniqueIDInConstructor() {
+int GetUniqueIDInConstructor() {
   static int unique_id_counter = 0;
   return ++unique_id_counter;
 }
 
-namespace content {
+void RecursivelyGenerateFrameEntries(const ExplodedFrameState& state,
+                                     NavigationEntryImpl::TreeNode* node) {
+  node->frame_entry = new FrameNavigationEntry(
+      -1, UTF16ToUTF8(state.target.string()), state.item_sequence_number,
+      state.document_sequence_number, nullptr, GURL(state.url_string.string()),
+      Referrer(GURL(state.referrer.string()), state.referrer_policy));
+
+  // Set a single-frame PageState on the entry.
+  ExplodedPageState page_state;
+  page_state.top = state;
+  std::string data;
+  if (EncodePageState(page_state, &data))
+    node->frame_entry->set_page_state(PageState::CreateFromEncodedData(data));
+
+  for (const ExplodedFrameState& child_state : state.children) {
+    NavigationEntryImpl::TreeNode* child_node =
+        new NavigationEntryImpl::TreeNode(nullptr);
+    node->children.push_back(child_node);
+    RecursivelyGenerateFrameEntries(child_state, child_node);
+  }
+}
+
+void RecursivelyGenerateFrameState(
+    NavigationEntryImpl::TreeNode* node,
+    ExplodedFrameState* state,
+    std::vector<base::NullableString16>* referenced_files) {
+  // The FrameNavigationEntry's PageState contains just the ExplodedFrameState
+  // for that particular frame.
+  ExplodedPageState exploded_page_state;
+  if (!DecodePageState(node->frame_entry->page_state().ToEncodedData(),
+                       &exploded_page_state)) {
+    NOTREACHED();
+    return;
+  }
+  ExplodedFrameState frame_state = exploded_page_state.top;
+
+  // Copy the FrameNavigationEntry's frame state into the destination state.
+  *state = frame_state;
+
+  // Copy the frame's files into the PageState's |referenced_files|.
+  referenced_files->reserve(referenced_files->size() +
+                            exploded_page_state.referenced_files.size());
+  for (auto& file : exploded_page_state.referenced_files)
+    referenced_files->push_back(file);
+
+  state->children.resize(node->children.size());
+  for (size_t i = 0; i < node->children.size(); ++i) {
+    RecursivelyGenerateFrameState(node->children[i], &state->children[i],
+                                  referenced_files);
+  }
+}
+
+}  // namespace
 
 int NavigationEntryImpl::kInvalidBindings = -1;
 
@@ -180,22 +238,47 @@ const base::string16& NavigationEntryImpl::GetTitle() const {
 }
 
 void NavigationEntryImpl::SetPageState(const PageState& state) {
-  frame_tree_->frame_entry->set_page_state(state);
+  if (!SiteIsolationPolicy::UseSubframeNavigationEntries()) {
+    frame_tree_->frame_entry->set_page_state(state);
+    return;
+  }
 
-  if (SiteIsolationPolicy::UseSubframeNavigationEntries()) {
-    // Also get the root ISN and DSN out of the PageState.
-    ExplodedPageState exploded_state;
-    if (!DecodePageState(state.ToEncodedData(), &exploded_state))
-      return;
-    frame_tree_->frame_entry->set_item_sequence_number(
-        exploded_state.top.item_sequence_number);
-    frame_tree_->frame_entry->set_document_sequence_number(
-        exploded_state.top.document_sequence_number);
+  // This should only be called when restoring a NavigationEntry, so there
+  // should be no subframe FrameNavigationEntries yet.
+  DCHECK_EQ(0U, frame_tree_->children.size());
+
+  // If the PageState can't be parsed or has no children, just store it on the
+  // main frame's FrameNavigationEntry without recursively creating subframe
+  // entries.
+  ExplodedPageState exploded_state;
+  if (!DecodePageState(state.ToEncodedData(), &exploded_state) ||
+      exploded_state.top.children.size() == 0U) {
+    frame_tree_->frame_entry->set_page_state(state);
+    return;
   }
+
+  RecursivelyGenerateFrameEntries(exploded_state.top, frame_tree_.get());
 }
 
-const PageState& NavigationEntryImpl::GetPageState() const {
-  return frame_tree_->frame_entry->page_state();
+PageState NavigationEntryImpl::GetPageState() const {
+  // Just return the main frame's PageState in default Chrome, or if there are
+  // no subframe FrameNavigationEntries.
+  if (!SiteIsolationPolicy::UseSubframeNavigationEntries() ||
+      frame_tree_->children.size() == 0U)
+    return frame_tree_->frame_entry->page_state();
+
+  // When we're using subframe entries, each FrameNavigationEntry has a
+  // frame-specific PageState.  We combine these into an ExplodedPageState tree
+  // and generate a full PageState from it.
+  ExplodedPageState exploded_state;
+  RecursivelyGenerateFrameState(frame_tree_.get(), &exploded_state.top,
+                                &exploded_state.referenced_files);
+
+  std::string encoded_data;
+  if (!EncodePageState(exploded_state, &encoded_data))
+    return frame_tree_->frame_entry->page_state();
+
+  return PageState::CreateFromEncodedData(encoded_data);
 }
 
 void NavigationEntryImpl::SetPageID(int page_id) {

content/browser/frame_host/navigation_entry_impl.h

@@ -89,7 +89,7 @@ class CONTENT_EXPORT NavigationEntryImpl
   void SetTitle(const base::string16& title) override;
   const base::string16& GetTitle() const override;
   void SetPageState(const PageState& state) override;
-  const PageState& GetPageState() const override;
+  PageState GetPageState() const override;
   void SetPageID(int page_id) override;
   int32 GetPageID() const override;
   const base::string16& GetTitleForDisplay(

content/public/browser/navigation_entry.h

@@ -85,7 +85,7 @@ class NavigationEntry {
   // the format is modified in the future, we should still be able to deal with
   // older versions.
   virtual void SetPageState(const PageState& state) = 0;
-  virtual const PageState& GetPageState() const = 0;
+  virtual PageState GetPageState() const = 0;
 
   // Describes the current page that the tab represents. This is the ID that the
   // renderer generated for the page and is how we can tell new versus