Adding fullscreen mode access to chrome.fileBrowserPrivate API.

chrome/browser/resources/file_manager/js/image_editor/media_controls.js

Index: chrome/browser/resources/file_manager/js/image_editor/media_controls.js
diff --git a/chrome/browser/resources/file_manager/js/image_editor/media_controls.js b/chrome/browser/resources/file_manager/js/image_editor/media_controls.js
index 61406659ba2393705d262421ea74fd20e3a0ba9e..264ae657a04617d304e90b1f30e83979ffe691df 100644
--- a/chrome/browser/resources/file_manager/js/image_editor/media_controls.js
+++ b/chrome/browser/resources/file_manager/js/image_editor/media_controls.js
@@ -20,6 +20,9 @@ function MediaControls(mediaElement, containerElement) {
   this.setupPlaybackControls_();
 
   this.setupMediaEvents_();
+
+  this.document_.defaultView.addEventListener(
+      'resize', this.onWindowResize.bind(this));
 }
 
 /**
@@ -279,8 +282,28 @@ MediaControls.prototype.onVolumeMouseDown_ = function () {
 };
 
 MediaControls.prototype.onFullscreenButtonClick_ = function() {
-  this.fullscreenButton_.classList.toggle('on');
-  // TODO: invoke the actual full screen mode
+  if (chrome.fileBrowserPrivate) {
+    chrome.fileBrowserPrivate.toggleFullscreen();
+  }
+};
+
+MediaControls.prototype.onWindowResize = function() {
+  // There is no notification to tell us when the user enters/leaves the
+  // fullscreen mode using the built-in Chrome controls. All we can do is
+  // query the current fullscreen state.
+  // The best place to do it is a window resize handler.
+  if (chrome.fileBrowserPrivate) {
+    chrome.fileBrowserPrivate.isFullscreen(
+        this.updateFullscreenStatus_.bind(this));
+  }
+};
+
+MediaControls.prototype.updateFullscreenStatus_ = function(on) {
+  if (on) {
+    this.fullscreenButton_.classList.add('on');
+  } else {
+    this.fullscreenButton_.classList.remove('on');
+  }
 };
 
 /**