Allow cast extensions to go fullscreen

We need to implement a couple WebContentsDelegate functions in order to
enable fullscreen behaviours

Bug: b/128926264
Test: desktop cast_shell build w/ embedded video page
Change-Id: I7c5e95fb4f59b3369b35f770dcccff647bf7f899
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1585104Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Reviewed-by: Alex Sakhartchouk <alexst@chromium.org>
Commit-Queue: Alex Sakhartchouk <alexst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662622}

chromecast/browser/cast_extension_host.cc

@@ -105,4 +105,27 @@ void CastExtensionHost::Observe(int type,
   LoadInitialURL();
 }
 
+void CastExtensionHost::EnterFullscreenModeForTab(
+    content::WebContents* web_contents,
+    const GURL& origin,
+    const blink::WebFullscreenOptions& options) {
+  SetFullscreen(web_contents, true);
+}
+void CastExtensionHost::ExitFullscreenModeForTab(
+    content::WebContents* web_contents) {
+  SetFullscreen(web_contents, false);
+}
+bool CastExtensionHost::IsFullscreenForTabOrPending(
+    const content::WebContents* web_contents) const {
+  return is_fullscreen_;
+}
+
+void CastExtensionHost::SetFullscreen(content::WebContents* web_contents,
+                                      bool value) {
+  if (value == is_fullscreen_)
+    return;
+  is_fullscreen_ = value;
+  web_contents->GetRenderViewHost()->GetWidget()->SynchronizeVisualProperties();
+}
+
 }  // namespace chromecast

chromecast/browser/cast_extension_host.h

@@ -45,8 +45,17 @@ class CastExtensionHost : public extensions::ExtensionHost,
                               const base::string16& message,
                               int32_t line_no,
                               const base::string16& source_id) override;
+  void EnterFullscreenModeForTab(
+      content::WebContents* web_contents,
+      const GURL& origin,
+      const blink::WebFullscreenOptions& options) override;
+  void ExitFullscreenModeForTab(content::WebContents*) override;
+  bool IsFullscreenForTabOrPending(
+      const content::WebContents* web_contents) const override;
 
  private:
+  void SetFullscreen(content::WebContents* web_contents, bool value);
+
   // content::NotificationObserver implementation:
   void Observe(int type,
                const content::NotificationSource& source,
@@ -54,6 +63,7 @@ class CastExtensionHost : public extensions::ExtensionHost,
 
   content::NotificationRegistrar registrar_;
   content::BrowserContext* const browser_context_;
+  bool is_fullscreen_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(CastExtensionHost);
 };