Improve timing of frame attach/detach (see #3664)

- Move frame attachment from RenderFrameCreated to
  DidCommitProvisionalLoad. This has a number of advantages:
  - Significantly reduces the frequency of disconnects by avoiding
    the GetInterface/DidCommitNavigation race condition.
  - Stops connecting temporary frames (created during cross-origin
    navigation), making callback behavior more consistent.
- Split frame detach and destruction notifications into separate
  callbacks. OnFrameDetached now reflects a potentially recoverable
  state. Add a new OnFrameDestroyed callback for the unrecoverable
  destruction state.

libcef/renderer/frame_impl.cc

@@ -316,20 +316,23 @@ void CefFrameImpl::SendProcessMessage(CefProcessId target_process,
   }
 }
 
-void CefFrameImpl::OnAttached() {
-  // Called indirectly from RenderFrameCreated.
-  ConnectBrowserFrame(ConnectReason::RENDER_FRAME_CREATED);
-}
-
 void CefFrameImpl::OnWasShown() {
-  if (browser_connection_state_ == ConnectionState::DISCONNECTED) {
-    // Reconnect a frame that has exited the bfcache.
+  if (browser_connection_state_ == ConnectionState::DISCONNECTED &&
+      did_commit_provisional_load_) {
+    // Reconnect a frame that has exited the bfcache. We ignore temporary
+    // frames that have never called DidCommitProvisionalLoad.
     ConnectBrowserFrame(ConnectReason::WAS_SHOWN);
   }
 }
 
 void CefFrameImpl::OnDidCommitProvisionalLoad() {
   did_commit_provisional_load_ = true;
+  if (browser_connection_state_ == ConnectionState::DISCONNECTED) {
+    // Connect after RenderFrameImpl::DidCommitNavigation has potentially
+    // reset the BrowserInterfaceBroker in the browser process. See related
+    // comments in OnDisconnect.
+    ConnectBrowserFrame(ConnectReason::DID_COMMIT);
+  }
   MaybeInitializeScriptContext();
 }
 
@@ -473,8 +476,8 @@ void CefFrameImpl::ConnectBrowserFrame(ConnectReason reason) {
   if (VLOG_IS_ON(1)) {
     std::string reason_str;
     switch (reason) {
-      case ConnectReason::RENDER_FRAME_CREATED:
-        reason_str = "RENDER_FRAME_CREATED";
+      case ConnectReason::DID_COMMIT:
+        reason_str = "DID_COMMIT";
         break;
       case ConnectReason::WAS_SHOWN:
         reason_str = "WAS_SHOWN";

libcef/renderer/frame_impl.h

@@ -81,7 +81,6 @@ class CefFrameImpl
                           CefRefPtr<CefProcessMessage> message) override;
 
   // Forwarded from CefRenderFrameObserver.
-  void OnAttached();
   void OnWasShown();
   void OnDidCommitProvisionalLoad();
   void OnDidFinishLoad();
@@ -105,7 +104,7 @@ class CefFrameImpl
                            LocalFrameAction action);
 
   enum class ConnectReason {
-    RENDER_FRAME_CREATED,
+    DID_COMMIT,
     WAS_SHOWN,
     RETRY,
   };

libcef/renderer/render_frame_observer.cc

@@ -199,7 +199,6 @@ void CefRenderFrameObserver::AttachFrame(CefFrameImpl* frame) {
   DCHECK(frame);
   DCHECK(!frame_);
   frame_ = frame;
-  frame_->OnAttached();
 }
 
 void CefRenderFrameObserver::OnLoadStart() {