Add content public APIs for Presentation API.

The pieces added are as follows:

1. PresentationServiceDelegate: An interface to be implemented by an
embedder to handle Presentation API requests. Includes an Observer
interface to observe the lifetime of the delegate object.
2. PresentationScreenAvailabilityListener: An interface to be
implemented by content/ code to receive screen availability results
from the embedder.
3. Added method to ContentBrowserClient: GetPresentationServiceDelegate.
Returns nullptr by default. Embedder may override it with an
implementation that can handle Presentation API requests. Added to
allow content/ code to obtain a reference to a
PresentationServiceDelegate to forward presentation API requests to.

Presentation Mojo service patch: crrev.com/839773002/
Blink plumbing: crrev.com/832263007

The Chrome implementation of PresentationServiceDelegate is currently
in a private repo.

BUG=412331

Review URL: https://codereview.chromium.org/883953002

Cr-Commit-Position: refs/heads/master@{#313563}

content/content_browser.gypi

@@ -178,6 +178,8 @@
       'public/browser/plugin_service.h',
       'public/browser/plugin_service_filter.h',
       'public/browser/power_save_blocker.h',
+      'public/browser/presentation_screen_availability_listener.h',
+      'public/browser/presentation_service_delegate.h',
       'public/browser/profiler_controller.h',
       'public/browser/profiler_subscriber.h',
       'public/browser/push_messaging_service.h',

content/public/browser/content_browser_client.cc

@@ -336,6 +336,12 @@ bool ContentBrowserClient::CheckMediaAccessPermission(
   return false;
 }
 
+PresentationServiceDelegate*
+ContentBrowserClient::GetPresentationServiceDelegate(
+    WebContents* web_contents) {
+  return nullptr;
+}
+
 #if defined(OS_WIN)
 const wchar_t* ContentBrowserClient::GetResourceDllName() {
   return nullptr;

content/public/browser/content_browser_client.h

@@ -96,6 +96,7 @@ class MediaObserver;
 class NavigatorConnectContext;
 class NavigatorConnectServiceFactory;
 class PlatformNotificationService;
+class PresentationServiceDelegate;
 class QuotaPermissionContext;
 class RenderFrameHost;
 class RenderProcessHost;
@@ -602,6 +603,11 @@ class CONTENT_EXPORT ContentBrowserClient {
       RenderFrameHost* render_frame_host,
       blink::WebPageVisibilityState* visibility_state) {}
 
+  // Allows an embedder to provide its own PresentationServiceDelegate
+  // implementation. Returns nullptr if unavailable.
+  virtual PresentationServiceDelegate* GetPresentationServiceDelegate(
+      WebContents* web_contents);
+
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
   // Populates |mappings| with all files that need to be mapped before launching
   // a child process.

content/public/browser/presentation_screen_availability_listener.h

+// Copyright 2015 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 CONTENT_PUBLIC_BROWSER_PRESENTATION_SCREEN_AVAILABILITY_LISTENER_H_
+#define CONTENT_PUBLIC_BROWSER_PRESENTATION_SCREEN_AVAILABILITY_LISTENER_H_
+
+#include <string>
+
+namespace content {
+
+// A listener interface used for receiving updates on screen availability
+// associated with a presentation URL from an embedder.
+// See also PresentationServiceDelegate.
+class PresentationScreenAvailabilityListener {
+ public:
+  // Returns the Presentation URL associated with this listener.
+  virtual std::string GetPresentationUrl() = 0;
+
+  // Called when screen availability for the associated Presentation URL has
+  // changed to |available|.
+  virtual void OnScreenAvailabilityChanged(bool available) = 0;
+
+ protected:
+  virtual ~ScreenAvailabilityListener() {}
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_PRESENTATION_SCREEN_AVAILABILITY_LISTENER_H_
+

content/public/browser/presentation_service_delegate.h

+// Copyright 2015 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 CONTENT_PUBLIC_BROWSER_PRESENTATION_SERVICE_DELEGATE_H_
+#define CONTENT_PUBLIC_BROWSER_PRESENTATION_SERVICE_DELEGATE_H_
+
+namespace content {
+
+class PresentationScreenAvailabilityListener;
+
+// An interface implemented by embedders to handle presentation API calls
+// forwarded from PresentationServiceImpl.
+class PresentationServiceDelegate {
+ public:
+  // Observer interface to listen for changes to PresentationServiceDelegate.
+  class Observer {
+   public:
+    // Called when the PresentationServiceDelegate is being destroyed.
+    virtual void OnDelegateDestroyed() = 0;
+
+   protected:
+    virtual ~Observer() {}
+  };
+
+  // Registers an observer with this class to listen for updates to this class.
+  // This class does not own the observer.
+  // It is an error to add an observer if it has already been added before.
+  virtual void AddObserver(Observer* observer) = 0;
+  // Unregisters an observer with this class.
+  virtual void RemoveObserver(Observer* observer) = 0;
+
+  // Registers |listener| to continuously listen for
+  // availability updates for a presentation URL, originated from the frame
+  // given by |render_process_id| and |render_frame_id|.
+  // This class does not own |listener|.
+  // Returns true on success.
+  // This call will return false if a listener with the same presentation URL
+  // from the same frame is already registered.
+  virtual bool AddScreenAvailabilityListener(
+      int render_process_id,
+      int render_frame_id,
+      PresentationScreenAvailabilityListener* listener) = 0;
+
+  // Unregisters |listener| originated from the frame given by
+  // |render_process_id| and |render_frame_id| from this class. The listener
+  // will no longer receive availability updates.
+  virtual void RemoveScreenAvailabilityListener(
+      int render_process_id,
+      int render_frame_id,
+      PresentationScreenAvailabilityListener* listener) = 0;
+
+  // Unregisters all listeners associated with the frame given by
+  // |render_process_id| and |render_frame_id|.
+  virtual void RemoveAllScreenAvailabilityListeners(
+      int render_process_id,
+      int render_frame_id) = 0;
+
+ protected:
+  virtual ~PresentationServiceDelegate() {}
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_PRESENTATION_SERVICE_DELEGATE_H_