[Chromecast] Add CastWebContents

chromecast/browser/cast_web_view.h

+// 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.
+
+#ifndef CHROMECAST_BROWSER_CAST_WEB_VIEW_H_
+#define CHROMECAST_BROWSER_CAST_WEB_VIEW_H_
+
+#include <memory>
+#include <string>
+
+#include "base/memory/weak_ptr.h"
+#include "chromecast/browser/cast_content_window.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_delegate.h"
+#include "content/public/browser/web_contents_observer.h"
+
+namespace content {
+class BrowserContext;
+class RenderViewHost;
+}
+
+namespace chromecast {
+
+// A simplified interface for loading and displaying WebContents in cast_shell.
+class CastWebView : content::WebContentsObserver,
+                    content::WebContentsDelegate {
+ public:
+  class Delegate : public shell::CastContentWindow::Delegate {
+   public:
+    // Called when the page has stopped. ie: A 404 occured when loading the page
+    // or if the render process crashes. |error_code| will return a net error

[alokp, 2017/01/18 05:10:56]

nit: "net error" -> net::Error

[derekjchow1, 2017/01/19 01:22:11]

Done.

+    // describing the failure, or net::OK if the page closed naturally.
+    virtual void OnPageStopped(int error_code) = 0;
+
+    // Called during WebContentsDelegate::LoadingStateChanged.
+    // |loading| indicates if web_contents_ IsLoading or not.
+    virtual void OnLoadingStateChanged(bool loading) = 0;
+  };
+
+  // |delegate| and |browser_context| should outlive the lifetime of this
+  // object.
+  CastWebView(Delegate* delegate, content::BrowserContext* browser_context,
+              bool transparent);
+  ~CastWebView() override;
+
+  shell::CastContentWindow* window() const {
+    return window_.get();
+  }
+
+  content::WebContents* web_contents() const {
+    return web_contents_.get();
+  }
+
+  // Navigates to |url|. The loaded page will be preloaded if MakeVisible has
+  // not been called on the object.
+  void LoadUrl(GURL url);

[alokp, 2017/01/18 05:10:56]

Can this be called multiple times with a different URL? Do we have such a
usecase? Can we pass the url in constructor if not?

[derekjchow1, 2017/01/19 01:22:11]

Done.

+
+  // Closes the page.
+  void ClosePage();

[alokp, 2017/01/18 05:10:56]

Why do we need this API? Can't we just delete the instance of this class?

[derekjchow1, 2017/01/19 01:22:11]

Calling ClosePage begins the closing process, which should trigger
document.unload() and other clean up activities. A consumer of CastWebView can
determine when the process has finished via OnPageStopped().

Deleting this class should force kill this page, which isn't always desirable.
We need this API to distinguish between graceful and force shutdown. I've
updated the comment to clarify purpose.

[alokp, 2017/01/19 05:26:36]

In that case this function should take a completion callback instead of an
out-of-band notification on a client object.

That said, I do not see the existing client waiting for the notification. Can we
add it when we actually need it?

[derekjchow1, 2017/01/19 21:59:16]

I disagree. We should handle page stops the same way, regardless if it was
triggered by a ClosePage() call, the page closing itself or the render process
dying. Having two APIs to know when the page stopped could leave to some
confusion and corner cases (eg. "will the callback or delegate be called first?"
or "what happens if the page crashes during document.onunload?"). Having a
single API like OnPageStopped that provides a reason as to why the page closed
is much simpler to understand and maintain.
See other comments. Although this isn't used publicly, this is required for
internal use.

+
+  // Makes the page visible to the user.
+  void MakeVisible();

[alokp, 2017/01/18 05:10:56]

nit: Show

[derekjchow1, 2017/01/19 01:22:12]

Done.

+
+ private:
+  // WebContentsObserver implementation:
+  void RenderProcessGone(base::TerminationStatus status) override;
+  void RenderViewCreated(content::RenderViewHost* render_view_host) override;
+  void DidFailProvisionalLoad(content::RenderFrameHost* render_frame_host,
+                              const GURL& validated_url,
+                              int error_code,
+                              const base::string16& error_description,
+                              bool was_ignored_by_handler) override;
+  void DidFailLoad(content::RenderFrameHost* render_frame_host,
+                   const GURL& validated_url,
+                   int error_code,
+                   const base::string16& error_description,
+                   bool was_ignored_by_handler) override;
+  void DidFirstVisuallyNonEmptyPaint() override;
+  void MediaStartedPlaying(const MediaPlayerInfo& media_info,
+                           const MediaPlayerId& id) override;
+  void MediaStoppedPlaying(const MediaPlayerInfo& media_info,
+                           const MediaPlayerId& id) override;
+
+  // WebContentsDelegate implementation:
+  content::WebContents* OpenURLFromTab(
+      content::WebContents* source,
+      const content::OpenURLParams& params) override;
+  void CloseContents(content::WebContents* source) override;
+  void LoadingStateChanged(content::WebContents* source,
+                           bool to_different_document) override;
+  void ActivateContents(content::WebContents* contents) override;
+#if defined(OS_ANDROID)
+  base::android::ScopedJavaLocalRef<jobject> GetContentVideoViewEmbedder()
+      override;
+#endif  // defined(OS_ANDROID)
+
+  void DelayedCloseContents();
+
+  Delegate* const delegate_;
+  content::BrowserContext* const browser_context_;
+  const bool transparent_;
+  const std::unique_ptr<shell::CastContentWindow> window_;
+  std::unique_ptr<content::WebContents> web_contents_;
+
+  base::WeakPtrFactory<CastWebView> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(CastWebView);
+};
+
+}  // namespace chromecast
+
+#endif  // CHROMECAST_BROWSER_CAST_WEB_VIEW_H_