[api-minor] Let getAnnotations fetch all annotations by default, unless an intent is specified

Currently `getAnnotations` will *only* fetch annotations that are either `viewable` or `printable`. This is "hidden" inside the `core.js` file, meaning that API consumers might be confused as to why they are not recieving *all* the annotations present for a page.

I thus think that the API should, by default, return *all* available annotations unless specifically told otherwise. In e.g. the default viewer, we obviously only want to display annotations that are `viewable`, hence this patch adds an `intent` parameter to `getAnnotations` that makes it possible to decide if only `viewable` or `printable` annotations should be fetched.

src/core/core.js

@@ -252,10 +252,16 @@ var Page = (function PageClosure() {
       });
     },
 
-    getAnnotationsData: function Page_getAnnotationsData() {
+    getAnnotationsData: function Page_getAnnotationsData(intent) {
       var annotations = this.annotations;
       var annotationsData = [];
       for (var i = 0, n = annotations.length; i < n; ++i) {
+        if (intent) {
+          if (!(intent === 'display' && annotations[i].viewable) &&
+              !(intent === 'print' && annotations[i].printable)) {
+            continue;
+          }
+        }
         annotationsData.push(annotations[i].data);
       }
       return annotationsData;
@@ -268,7 +274,7 @@ var Page = (function PageClosure() {
       for (var i = 0, n = annotationRefs.length; i < n; ++i) {
         var annotationRef = annotationRefs[i];
         var annotation = annotationFactory.create(this.xref, annotationRef);
-        if (annotation && (annotation.viewable || annotation.printable)) {
+        if (annotation) {
           annotations.push(annotation);
         }
       }

src/core/worker.js

@@ -399,7 +399,7 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
 
     handler.on('GetDestination',
       function wphSetupGetDestination(data) {
-        return pdfManager.ensureCatalog('getDestination', [ data.id ]);
+        return pdfManager.ensureCatalog('getDestination', [data.id]);
       }
     );
 
@@ -447,7 +447,7 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
 
     handler.on('GetAnnotations', function wphSetupGetAnnotations(data) {
       return pdfManager.getPage(data.pageIndex).then(function(page) {
-        return pdfManager.ensure(page, 'getAnnotationsData', []);
+        return pdfManager.ensure(page, 'getAnnotationsData', [data.intent]);
       });
     });
 

src/display/api.js

@@ -649,6 +649,16 @@ var PDFDocumentProxy = (function PDFDocumentProxyClosure() {
  * @property {string} fontFamily - possible font family
  */
 
+/**
+ * Page annotation parameters.
+ *
+ * @typedef {Object} GetAnnotationsParameters
+ * @param {string} intent - Determines the annotations that will be fetched,
+ *                 can be either 'display' (viewable annotations) or 'print'
+ *                 (printable annotations).
+ *                 If the parameter is omitted, all annotations are fetched.
+ */
+
 /**
  * Page render parameters.
  *
@@ -737,12 +747,17 @@ var PDFPageProxy = (function PDFPageProxyClosure() {
       return new PDFJS.PageViewport(this.view, scale, rotate, 0, 0);
     },
     /**
+     * @param {GetAnnotationsParameters} params - Annotation parameters.
      * @return {Promise} A promise that is resolved with an {Array} of the
      * annotation objects.
      */
-    getAnnotations: function PDFPageProxy_getAnnotations() {
-      if (!this.annotationsPromise) {
-        this.annotationsPromise = this.transport.getAnnotations(this.pageIndex);
+    getAnnotations: function PDFPageProxy_getAnnotations(params) {
+      var intent = (params && params.intent) || null;
+
+      if (!this.annotationsPromise || this.annotationsIntent !== intent) {
+        this.annotationsPromise = this.transport.getAnnotations(this.pageIndex,
+                                                                intent);
+        this.annotationsIntent = intent;
       }
       return this.annotationsPromise;
     },
@@ -1470,9 +1485,11 @@ var WorkerTransport = (function WorkerTransportClosure() {
       return this.messageHandler.sendWithPromise('GetPageIndex', { ref: ref });
     },
 
-    getAnnotations: function WorkerTransport_getAnnotations(pageIndex) {
-      return this.messageHandler.sendWithPromise('GetAnnotations',
-        { pageIndex: pageIndex });
+    getAnnotations: function WorkerTransport_getAnnotations(pageIndex, intent) {
+      return this.messageHandler.sendWithPromise('GetAnnotations', {
+        pageIndex: pageIndex,
+        intent: intent,
+      });
     },
 
     getDestinations: function WorkerTransport_getDestinations() {
@@ -1480,7 +1497,7 @@ var WorkerTransport = (function WorkerTransportClosure() {
     },
 
     getDestination: function WorkerTransport_getDestination(id) {
-      return this.messageHandler.sendWithPromise('GetDestination', { id: id } );
+      return this.messageHandler.sendWithPromise('GetDestination', { id: id });
     },
 
     getAttachments: function WorkerTransport_getAttachments() {