Disable PresentationMode for certain problematic configurations

Instead of trying to hack around various browser defects, let's just disable PresentationMode in the affected browsers. This patch:

- Disables PresentationMode in IE11+ when the viewer is embedded; fixes 4711.

src/display/api.js

@@ -44,7 +44,7 @@ PDFJS.cMapUrl = (PDFJS.cMapUrl === undefined ? null : PDFJS.cMapUrl);
  */
 PDFJS.cMapPacked = PDFJS.cMapPacked === undefined ? false : PDFJS.cMapPacked;
 
-/*
+/**
  * By default fonts are converted to OpenType fonts and loaded via font face
  * rules. If disabled, the font will be rendered using a built in font renderer
  * that constructs the glyphs with primitive path commands.
@@ -134,6 +134,14 @@ PDFJS.disableCreateObjectURL = (PDFJS.disableCreateObjectURL === undefined ?
 PDFJS.disableWebGL = (PDFJS.disableWebGL === undefined ?
                       true : PDFJS.disableWebGL);
 
+/**
+ * Disables fullscreen support, and by extension Presentation Mode,
+ * in browsers which support the fullscreen API.
+ * @var {boolean}
+ */
+PDFJS.disableFullscreen = (PDFJS.disableFullscreen === undefined ?
+                           false : PDFJS.disableFullscreen);
+
 /**
  * Enables CSS only zooming.
  * @var {boolean}

web/compatibility.js

@@ -562,3 +562,13 @@ if (typeof PDFJS === 'undefined') {
     PDFJS.maxCanvasPixels = 5242880;
   }
 })();
+
+// Disable fullscreen support for certain problematic configurations.
+// Support: IE11+ (when embedded).
+(function checkFullscreenSupport() {
+  var isEmbeddedIE = (navigator.userAgent.indexOf('Trident') >= 0 &&
+                      window.parent !== window);
+  if (isEmbeddedIE) {
+    PDFJS.disableFullscreen = true;
+  }
+})();

web/viewer.js

@@ -322,6 +322,9 @@ var PDFViewerApplication = {
         document.msFullscreenEnabled === false) {
       support = false;
     }
+    if (support && PDFJS.disableFullscreen === true) {
+      support = false;
+    }
 
     return PDFJS.shadow(this, 'supportsFullscreen', support);
   },