Enable Picture-in-Picture for extensions.

This CL enables Picture-in-Picture in extensions by implementing
EnterPictureInPicture and ExitPictureInPicture in ExtensionHostDelegate.

Change-Id: I77522e345b7fed7d4515e81204a635a5ed8ecb6c
Bug: 726619
Reviewed-on: https://chromium-review.googlesource.com/1145261
Commit-Queue: François Beaufort <[email protected]>
Reviewed-by: Sadrul Chowdhury <[email protected]>
Reviewed-by: Devlin <[email protected]>
Reviewed-by: Sergey Volk <[email protected]>
Cr-Commit-Position: refs/heads/master@{#586632}
diff --git a/extensions/browser/extension_host.h b/extensions/browser/extension_host.h
index bd05034..db4489f 100644
--- a/extensions/browser/extension_host.h
+++ b/extensions/browser/extension_host.h
@@ -127,6 +127,9 @@
                                   const GURL& security_origin,
                                   content::MediaStreamType type) override;
   bool IsNeverVisible(content::WebContents* web_contents) override;
+  gfx::Size EnterPictureInPicture(const viz::SurfaceId& surface_id,
+                                  const gfx::Size& natural_size) override;
+  void ExitPictureInPicture() override;
 
   // ExtensionRegistryObserver:
   void OnExtensionReady(content::BrowserContext* browser_context,