Factor out RenderWidgetHostConnector

content/browser/android/render_widget_host_connector.cc

+// Copyright 2017 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/android/render_widget_host_connector.h"
+
+#include "content/browser/frame_host/interstitial_page_impl.h"
+#include "content/browser/renderer_host/render_widget_host_view_android.h"
+#include "content/browser/web_contents/web_contents_impl.h"
+
+namespace content {
+
+// Observes RenderWidgetHostViewAndroid to keep the instance up to date.
+class RenderWidgetHostConnector::Observer
+    : public WebContentsObserver,
+      public RenderWidgetHostViewAndroid::DestructionObserver {
+ public:
+  Observer(WebContents* web_contents, RenderWidgetHostConnector* connector);
+  ~Observer() override;
+
+  // WebContentsObserver implementation.
+  void RenderViewReady() override;
+  void RenderViewHostChanged(RenderViewHost* old_host,
+                             RenderViewHost* new_host) override;
+  void DidAttachInterstitialPage() override;
+  void DidDetachInterstitialPage() override;
+  void WebContentsDestroyed() override;
+
+  // RenderWidgetHostViewAndroid::DestructionObserver implementation.
+  void RenderWidgetHostViewDestroyed(
+      RenderWidgetHostViewAndroid* rwhva) override;
+
+  RenderWidgetHostViewAndroid* main_rwhva() const { return main_rwhva_; }
+  RenderWidgetHostViewAndroid* interstitial_rwhva() const {
+    return interstitial_rwhva_;
+  }
+
+ private:
+  void UpdateRenderWidgetHostView(RenderWidgetHostViewAndroid* old_rwhva,
+                                  RenderWidgetHostViewAndroid* new_rwhva);
+  RenderWidgetHostViewAndroid* GetRenderWidgetHostViewAndroid() const;
+
+  RenderWidgetHostConnector* const connector_;
+
+  // Active RenderWidgetHostView connected to this instance.
+  // Note that |main_rwhva_| points to the inactive one in the background
+  // (rather than nulled out) while an interstitial page is showing.
+  RenderWidgetHostViewAndroid* main_rwhva_;
+  RenderWidgetHostViewAndroid* interstitial_rwhva_;
+
+  DISALLOW_COPY_AND_ASSIGN(Observer);
+};
+
+RenderWidgetHostConnector::Observer::Observer(
+    WebContents* web_contents,
+    RenderWidgetHostConnector* connector)
+    : WebContentsObserver(web_contents),
+      connector_(connector),
+      main_rwhva_(nullptr),
+      interstitial_rwhva_(nullptr) {}
+
+RenderWidgetHostConnector::Observer::~Observer() {
+  DCHECK(!main_rwhva_);
+}
+
+void RenderWidgetHostConnector::Observer::RenderViewReady() {
+  auto* new_rwhva = GetRenderWidgetHostViewAndroid();
+  UpdateRenderWidgetHostView(main_rwhva_, new_rwhva);
+  main_rwhva_ = new_rwhva;
+}
+
+void RenderWidgetHostConnector::Observer::RenderViewHostChanged(
+    RenderViewHost* old_host,
+    RenderViewHost* new_host) {
+  auto* new_view = new_host ? static_cast<RenderWidgetHostViewAndroid*>(
+                                  new_host->GetWidget()->GetView())
+                            : nullptr;
+
+  // |RenderViewHostChanged| is called only for main rwhva change.
+  // No need to update connection if an interstitial page is active.
+  if (!interstitial_rwhva_)
+    UpdateRenderWidgetHostView(main_rwhva_, new_view);
+  main_rwhva_ = new_view;
+}
+
+void RenderWidgetHostConnector::Observer::DidAttachInterstitialPage() {
+  auto* new_rwhva = GetRenderWidgetHostViewAndroid();
+  UpdateRenderWidgetHostView(main_rwhva_, new_rwhva);
+  interstitial_rwhva_ = new_rwhva;
+}
+
+void RenderWidgetHostConnector::Observer::DidDetachInterstitialPage() {
+  auto* new_rwhva = GetRenderWidgetHostViewAndroid();
+  UpdateRenderWidgetHostView(interstitial_rwhva_, new_rwhva);
+  interstitial_rwhva_ = nullptr;
+  main_rwhva_ = new_rwhva;
+}
+
+void RenderWidgetHostConnector::Observer::WebContentsDestroyed() {
+  auto* cur_rwhva = interstitial_rwhva_ ? interstitial_rwhva_ : main_rwhva_;
+  DCHECK_EQ(cur_rwhva, GetRenderWidgetHostViewAndroid());
+  UpdateRenderWidgetHostView(cur_rwhva, nullptr);
+  interstitial_rwhva_ = nullptr;
+  main_rwhva_ = nullptr;
+  delete connector_;
+}
+
+void RenderWidgetHostConnector::Observer::RenderWidgetHostViewDestroyed(
+    RenderWidgetHostViewAndroid* destroyed_rwhva) {
+  // Null out the matched raw pointer here and in the connector impl to keep
+  // them from referencing the rwvha about to be destroyed.
+  if (destroyed_rwhva == interstitial_rwhva_) {
+    connector_->UpdateRenderProcessConnection(interstitial_rwhva_, nullptr);
+    interstitial_rwhva_ = nullptr;
+  } else if (destroyed_rwhva == main_rwhva_) {
+    if (!interstitial_rwhva_)
+      connector_->UpdateRenderProcessConnection(main_rwhva_, nullptr);
+    main_rwhva_ = nullptr;
+  }
+}
+
+void RenderWidgetHostConnector::Observer::UpdateRenderWidgetHostView(
+    RenderWidgetHostViewAndroid* old_rwhva,
+    RenderWidgetHostViewAndroid* new_rwhva) {
+  if (old_rwhva == new_rwhva)
+    return;
+  if (old_rwhva)
+    old_rwhva->RemoveDestructionObserver(this);

[boliu, 2017/04/15 00:52:54]

this doesn't work anymore. I think you need to observe destructor on both
interstitial and regular rwhva?

[Jinsuk Kim, 2017/04/15 01:19:07]

At certain time there is (and should be) only one rwhva (active) that keeps the
observer in its list. I made sure the |old_rwhva| is the one that was keeping
this observer. So I think this will still work. Do you see a bug?

[boliu, 2017/04/15 02:06:21]

what if the non-interstitial rwhva is destroyed while interstitial is showing?

[Jinsuk Kim, 2017/04/16 23:16:43]

Main rwhva is not connected to ime, so its destruction doesn't affect much. It
is handled in ::RenderWidgetHostViewDestroyed where |main_rwhva_| will be set to
null, and interstitial keeps its connection to the ime. So I think it will still
work?

+  if (new_rwhva)
+    new_rwhva->AddDestructionObserver(this);
+
+  connector_->UpdateRenderProcessConnection(old_rwhva, new_rwhva);
+}
+
+RenderWidgetHostViewAndroid*
+RenderWidgetHostConnector::Observer::GetRenderWidgetHostViewAndroid() const {
+  RenderWidgetHostView* rwhv = web_contents()->GetRenderWidgetHostView();
+  WebContentsImpl* web_contents_impl =
+      static_cast<WebContentsImpl*>(web_contents());
+  if (web_contents_impl->ShowingInterstitialPage()) {
+    rwhv = web_contents_impl->GetInterstitialPage()
+               ->GetMainFrame()
+               ->GetRenderViewHost()
+               ->GetWidget()
+               ->GetView();
+  }
+  return static_cast<RenderWidgetHostViewAndroid*>(rwhv);
+}
+
+RenderWidgetHostConnector::RenderWidgetHostConnector(WebContents* web_contents)
+    : render_widget_observer_(new Observer(web_contents, this)) {}
+
+RenderWidgetHostConnector::~RenderWidgetHostConnector() {}
+
+RenderWidgetHostViewAndroid* RenderWidgetHostConnector::GetMainRWHVAForTesting()
+    const {
+  return render_widget_observer_->main_rwhva();
+}
+
+RenderWidgetHostViewAndroid*
+RenderWidgetHostConnector::GetInterstitialRWHVAForTesting() const {
+  return render_widget_observer_->interstitial_rwhva();
+}
+
+}  // namespace content