[ChromeDriver] Lock parent WebView with child in use

When a WebView is in use, lock all its parents, to avoid dangling WebView.

Bug: chromedriver:3383
Change-Id: I3503e35922c45d7d9b1b244877486512d16124bd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2099583Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#749429}

chrome/test/chromedriver/chrome/web_view_impl.cc

@@ -1200,16 +1200,32 @@ std::unique_ptr<base::Value> WebViewImpl::GetCastIssueMessage() {
   return std::unique_ptr<base::Value>(cast_tracker_->issue().DeepCopy());
 }
 
-WebViewImplHolder::WebViewImplHolder(WebViewImpl* web_view)
-    : web_view_(web_view), was_locked_(web_view && web_view->Lock()) {}
+WebViewImplHolder::WebViewImplHolder(WebViewImpl* web_view) {
+  // Lock input web view and all its parents, to prevent them from being
+  // deleted while still in use. Inside |items_|, each web view must appear
+  // before its parent. This ensures the destructor unlocks the web views in
+  // the right order.
+  while (web_view != nullptr) {
+    Item item;
+    item.web_view = web_view;
+    item.was_locked = web_view->Lock();
+    items_.push_back(item);
+    web_view = const_cast<WebViewImpl*>(web_view->GetParent());
+  }
+}
 
 WebViewImplHolder::~WebViewImplHolder() {
-  if (web_view_ != nullptr && !was_locked_) {
-    if (!web_view_->IsDetached())
-      web_view_->Unlock();
-    else if (web_view_->GetParent() != nullptr)
-      web_view_->GetParent()->GetFrameTracker()->DeleteTargetForFrame(
-          web_view_->GetId());
+  for (Item& item : items_) {
+    // Once we find a web view that is still locked, then all its parents must
+    // also be locked.
+    if (item.was_locked)
+      break;
+    WebViewImpl* web_view = item.web_view;
+    if (!web_view->IsDetached())
+      web_view->Unlock();
+    else if (web_view->GetParent() != nullptr)
+      web_view->GetParent()->GetFrameTracker()->DeleteTargetForFrame(
+          web_view->GetId());
   }
 }
 

chrome/test/chromedriver/chrome/web_view_impl.h

@@ -226,8 +226,11 @@ class WebViewImplHolder {
   ~WebViewImplHolder();
 
  private:
-  WebViewImpl* web_view_;
-  bool was_locked_;
+  struct Item {
+    WebViewImpl* web_view;
+    bool was_locked;
+  };
+  std::vector<Item> items_;
 
   DISALLOW_COPY_AND_ASSIGN(WebViewImplHolder);
 };