PlzNavigate: AppCache support.

content/browser/appcache/appcache_navigation_handle_core.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/appcache/appcache_navigation_handle_core.h"
+
+#include <utility>
+
+#include "base/bind.h"
+#include "content/browser/appcache/appcache_dispatcher_host.h"
+#include "content/browser/appcache/appcache_host.h"
+#include "content/browser/appcache/appcache_navigation_handle.h"
+#include "content/browser/appcache/appcache_service_impl.h"
+#include "content/browser/appcache/chrome_appcache_service.h"
+
+namespace content {
+
+AppCacheNavigationHandleCore::AppCacheNavigationHandleCore(
+    base::WeakPtr<AppCacheNavigationHandle> ui_handle,
+    ChromeAppCacheService* appcache_service,
+    int appcache_host_id)
+    : appcache_service_(appcache_service),
+      appcache_host_id_(appcache_host_id),
+      ui_handle_(ui_handle) {
+  // The AppCacheNavigationHandleCore is created on the UI thread but
+  // should only be accessed from the IO thread afterwards.
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+}
+
+AppCacheNavigationHandleCore::~AppCacheNavigationHandleCore() {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  if (precreated_host_.get())

[michaeln, 2016/12/03 00:58:58]

is the test and reset call explicitly needed, std::unique_ptr<> should do this
for us?

[ananta, 2016/12/03 14:55:04]

Done.

+    precreated_host_.reset(nullptr);
+}
+
+void AppCacheNavigationHandleCore::Initialize() {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK(precreated_host_.get() == nullptr);
+  precreated_host_.reset(
+      new AppCacheHost(appcache_host_id_, this, GetAppCacheService()));
+}
+
+void AppCacheNavigationHandleCore::CommitNavigation(int process_id) {
+  scoped_refptr<AppCacheDispatcherHost> dispatcher_host =
+      AppCacheDispatcherHost::GetHostForProcess(process_id);

[michaeln, 2016/12/03 00:58:58]

ah... the map is accessed on the IO thread

Maybe we don't need the map since we have a AppCacheService ptr and from that
can get to the AppcacheBackend, see AppCacheServiceImpl::GetBackend(id). If
collection of 'pending_host_ids_' is kept in the backend, we might not need to
muck with the DispatcherHost at all.

[ananta, 2016/12/03 14:55:04]

The renderer process has not registered with the host at this point. Hence the
service
will not have any information about the backend. I tried this change and found
that
the renderer process registers after the top level navigation commit request
happens

+  // We release ownership of the precreated_host_ here. From this point on
+  // the AppCacheBackendImpl class owns the host.
+  if (dispatcher_host.get())
+    dispatcher_host->RegisterPrecreatedHost(std::move(precreated_host_));
+}
+
+AppCacheServiceImpl* AppCacheNavigationHandleCore::GetAppCacheService() {
+  return static_cast<AppCacheServiceImpl*>(appcache_service_.get());
+}
+
+void AppCacheNavigationHandleCore::OnCacheSelected(int host_id,
+                                                   const AppCacheInfo& info) {
+  DCHECK(false);
+}
+
+void AppCacheNavigationHandleCore::OnStatusChanged(
+    const std::vector<int>& host_ids,
+    AppCacheStatus status) {
+  // Should never be called.
+  DCHECK(false);
+}
+
+void AppCacheNavigationHandleCore::OnEventRaised(
+    const std::vector<int>& host_ids,
+    AppCacheEventID event_id) {
+  // Should never be called.
+  DCHECK(false);
+}
+
+void AppCacheNavigationHandleCore::OnProgressEventRaised(
+    const std::vector<int>& host_ids,
+    const GURL& url,
+    int num_total,
+    int num_complete) {
+  // Should never be called.
+  DCHECK(false);
+}
+
+void AppCacheNavigationHandleCore::OnErrorEventRaised(
+    const std::vector<int>& host_ids,
+    const AppCacheErrorDetails& details) {
+  // Should never be called.
+  DCHECK(false);
+}
+
+void AppCacheNavigationHandleCore::OnLogMessage(int host_id,
+                                                AppCacheLogLevel log_level,
+                                                const std::string& message) {
+  // Should never be called.
+  DCHECK(false);
+}
+
+void AppCacheNavigationHandleCore::OnContentBlocked(int host_id,
+                                                    const GURL& manifest_url) {
+  // Should never be called.
+  DCHECK(false);
+}
+
+}  // namespace content