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* active_rwhva() const { return active_rwhva_; }
+
+ private:
+  void UpdateRenderWidgetHostView(RenderWidgetHostViewAndroid* new_rwhva);
+  RenderWidgetHostViewAndroid* GetRenderWidgetHostViewAndroid() const;
+
+  RenderWidgetHostConnector* const connector_;
+
+  // Active RenderWidgetHostView connected to this instance. Can also point to
+  // an interstitial while it is showing.
+  RenderWidgetHostViewAndroid* active_rwhva_;
+
+  DISALLOW_COPY_AND_ASSIGN(Observer);
+};
+
+RenderWidgetHostConnector::Observer::Observer(
+    WebContents* web_contents,
+    RenderWidgetHostConnector* connector)
+    : WebContentsObserver(web_contents),
+      connector_(connector),
+      active_rwhva_(nullptr) {}
+
+RenderWidgetHostConnector::Observer::~Observer() {
+  DCHECK(!active_rwhva_);
+}
+
+void RenderWidgetHostConnector::Observer::RenderViewReady() {
+  UpdateRenderWidgetHostView(GetRenderWidgetHostViewAndroid());
+}
+
+void RenderWidgetHostConnector::Observer::RenderViewHostChanged(
+    RenderViewHost* old_host,
+    RenderViewHost* new_host) {
+  // |RenderViewHostChanged| is called only for main rwhva change.
+  // No need to update connection if an interstitial page is active.
+  if (web_contents()->ShowingInterstitialPage())
+    return;
+
+  auto* new_view = new_host ? static_cast<RenderWidgetHostViewAndroid*>(
+                                  new_host->GetWidget()->GetView())
+                            : nullptr;
+  UpdateRenderWidgetHostView(new_view);
+}
+
+void RenderWidgetHostConnector::Observer::DidAttachInterstitialPage() {
+  UpdateRenderWidgetHostView(GetRenderWidgetHostViewAndroid());
+}
+
+void RenderWidgetHostConnector::Observer::DidDetachInterstitialPage() {
+  UpdateRenderWidgetHostView(GetRenderWidgetHostViewAndroid());
+}
+
+void RenderWidgetHostConnector::Observer::WebContentsDestroyed() {
+  DCHECK_EQ(active_rwhva_, GetRenderWidgetHostViewAndroid());
+  UpdateRenderWidgetHostView(nullptr);
+  delete connector_;
+}
+
+void RenderWidgetHostConnector::Observer::RenderWidgetHostViewDestroyed(
+    RenderWidgetHostViewAndroid* destroyed_rwhva) {
+  // Null out the raw pointer here and in the connector impl to keep
+  // them from referencing the rwvha about to be destroyed.
+  if (destroyed_rwhva == active_rwhva_) {
+    connector_->UpdateRenderProcessConnection(active_rwhva_, nullptr);

[boliu, 2017/04/18 03:53:58]

should this just be UpdateRenderWidgetHostView(nullptr);?

[Jinsuk Kim, 2017/04/18 04:25:34]

This came from RWHVA destruction observer. So no need to (should not) do
something again to add observer to that RWHVA again.

[boliu, 2017/04/18 04:45:32]

Well, won't be adding observer because it's calling with null. And remove should
still be safe because we went over this, this is called in RWHVA::Destroy, not
destructor. If it's destructor, then it should not pass up the pointer at all
because it's not safe at that point.

[boliu, 2017/04/18 04:47:09]

Oh you mean it's not safe modifying the vector and iterating it at the same
time? Then maybe it should be a base::ObserverList

[Jinsuk Kim, 2017/04/18 05:20:23]

Done.

+    active_rwhva_ = nullptr;
+  }
+}
+
+void RenderWidgetHostConnector::Observer::UpdateRenderWidgetHostView(
+    RenderWidgetHostViewAndroid* new_rwhva) {
+  if (active_rwhva_ == new_rwhva)
+    return;
+  if (active_rwhva_)
+    active_rwhva_->RemoveDestructionObserver(this);
+  if (new_rwhva)
+    new_rwhva->AddDestructionObserver(this);
+
+  connector_->UpdateRenderProcessConnection(active_rwhva_, new_rwhva);
+  active_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::GetRWHVAForTesting()
+    const {
+  return render_widget_observer_->active_rwhva();
+}
+
+}  // namespace content