chrome: Update expectations with same-site BFCache enabled (fixes issue #3301)

With same-site BFCache enabled every navigation can now potentially be served
via the BFCache. To support this internally a new top-level RenderFrame object
may be created for each new navigation. As a result, OnBrowserCreated may now
be called multiple times with the same browser ID in a given renderer process
(a behavior previously only seen with cross-site navigations and different
renderer processes).

BFCache navigations do not trigger the same Chromium notifications as a normal
load. To avoid breaking CEF API usage expectations we now synthetically
generate the load-related callbacks that would otherwise be missing
(OnLoadingStateChange with isLoading=true, OnLoadStart, OnLoadEnd). The
|httpStatusCode| argument to OnLoadEnd will be 0 in this case.

To test:
- Run `FrameHandlerTest.*:MessageRouterTest.*:NavigationTest.*`
- Run `NavigationTest.LoadSameOriginLoadURL` for OnBrowserCreated behavior.
- Run `NavigationTest.History` for load-related callback behavior.

libcef/renderer/blink_glue.h

@@ -13,6 +13,7 @@
 
 #include "include/internal/cef_types.h"
 
+#include "third_party/blink/public/mojom/frame/lifecycle.mojom-blink-forward.h"
 #include "third_party/blink/public/platform/web_common.h"
 #include "v8/include/v8.h"
 
@@ -72,6 +73,32 @@ BLINK_EXPORT v8::Local<v8::Value> ExecuteV8ScriptAndReturnValue(
 
 BLINK_EXPORT bool IsScriptForbidden();
 
+class BLINK_EXPORT CefObserverRegistration {
+ public:
+  CefObserverRegistration() = default;
+
+  CefObserverRegistration(const CefObserverRegistration&) = delete;
+  CefObserverRegistration& operator=(const CefObserverRegistration&) = delete;
+
+  virtual ~CefObserverRegistration() = default;
+};
+
+class BLINK_EXPORT CefExecutionContextLifecycleStateObserver {
+ public:
+  virtual void ContextLifecycleStateChanged(
+      blink::mojom::blink::FrameLifecycleState state) {}
+
+ protected:
+  virtual ~CefExecutionContextLifecycleStateObserver() = default;
+};
+
+// Register an ExecutionContextLifecycleStateObserver. Remains registered until
+// the returned object is destroyed.
+BLINK_EXPORT std::unique_ptr<CefObserverRegistration>
+RegisterExecutionContextLifecycleStateObserver(
+    v8::Local<v8::Context> context,
+    CefExecutionContextLifecycleStateObserver* observer);
+
 BLINK_EXPORT void RegisterURLSchemeAsSupportingFetchAPI(
     const blink::WebString& scheme);