Move API specific compatibility options from src/shared/compatibility.js and into a separate file

Unfortunately, as far as I can tell, we still need the ability to adjust certain API options depending on the browser environment in PDF.js version `2.0`. However, we should be able to separate this from the general compatibility code in the `src/shared/compatibility.js` file.

src/display/api_compatibility.js

@@ -0,0 +1,50 @@
+/* Copyright 2018 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+let compatibilityParams = Object.create(null);
+if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC')) {
+  const userAgent =
+    (typeof navigator !== 'undefined' && navigator.userAgent) || '';
+  const isIE = /Trident/.test(userAgent);
+  const isIOS = /\b(iPad|iPhone|iPod)(?=;)/.test(userAgent);
+  const isIOSChrome = /CriOS/.test(userAgent);
+  const isSafari = /Safari\//.test(userAgent) &&
+                   !/(Chrome\/|Android\s)/.test(userAgent);
+
+  // Checks if possible to use URL.createObjectURL()
+  // Support: IE, Chrome on iOS
+  (function checkOnBlobSupport() {
+    // Sometimes IE and Chrome on iOS losing the data created with
+    // createObjectURL(), see issues #3977 and #8081.
+    if (isIE || isIOSChrome) {
+      compatibilityParams.disableCreateObjectURL = true;
+    }
+  })();
+
+  // Support: Safari 6.0+, iOS
+  (function checkRangeRequests() {
+    // Safari has issues with cached range requests, see issue #3260.
+    // Last tested with version 6.0.4.
+    if (isSafari || isIOS) {
+      compatibilityParams.disableRange = true;
+      compatibilityParams.disableStream = true;
+    }
+  })();
+}
+const apiCompatibilityParams = Object.freeze(compatibilityParams);
+
+export {
+  apiCompatibilityParams,
+};

src/pdf.js

@@ -29,6 +29,7 @@ var pdfjsDisplayAnnotationLayer = require('./display/annotation_layer.js');
 var pdfjsDisplayDOMUtils = require('./display/dom_utils.js');
 var pdfjsDisplaySVG = require('./display/svg.js');
 let pdfjsDisplayWorkerOptions = require('./display/worker_options.js');
+let pdfjsDisplayAPICompatibility = require('./display/api_compatibility.js');
 
 if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC')) {
   const isNodeJS = require('./shared/is_node.js');
@@ -96,3 +97,5 @@ exports.getFilenameFromUrl = pdfjsDisplayDOMUtils.getFilenameFromUrl;
 exports.LinkTarget = pdfjsDisplayDOMUtils.LinkTarget;
 exports.addLinkAttributes = pdfjsDisplayDOMUtils.addLinkAttributes;
 exports.GlobalWorkerOptions = pdfjsDisplayWorkerOptions.GlobalWorkerOptions;
+exports.apiCompatibilityParams =
+  pdfjsDisplayAPICompatibility.apiCompatibilityParams;

src/shared/compatibility.js

@@ -29,14 +29,7 @@ if (typeof PDFJSDev === 'undefined' || !PDFJSDev.test('CHROME')) {
 const globalScope = require('./global_scope');
 const isNodeJS = require('./is_node');
 
-var userAgent = (typeof navigator !== 'undefined' && navigator.userAgent) || '';
+const hasDOM = typeof window === 'object' && typeof document === 'object';
-var isIOSChrome = userAgent.indexOf('CriOS') >= 0;
-var isIE = userAgent.indexOf('Trident') >= 0;
-var isIOS = /\b(iPad|iPhone|iPod)(?=;)/.test(userAgent);
-var isSafari = /Safari\//.test(userAgent) &&
-               !/(Chrome\/|Android\s)/.test(userAgent);
-
-var hasDOM = typeof window === 'object' && typeof document === 'object';
 
 // Initializing PDFJS global object here, it case if we need to change/disable
 // some PDF.js features, e.g. range requests
@@ -68,27 +61,6 @@ PDFJS.compatibilityChecked = true;
   };
 })();
 
-// Checks if possible to use URL.createObjectURL()
-// Support: IE, Chrome on iOS
-(function checkOnBlobSupport() {
-  // sometimes IE and Chrome on iOS loosing the data created with
-  // createObjectURL(), see #3977 and #8081
-  if (isIE || isIOSChrome) {
-    PDFJS.disableCreateObjectURL = true;
-  }
-})();
-
-// Support: Safari 6.0+, iOS
-(function checkRangeRequests() {
-  // Safari has issues with cached range requests see:
-  // https://github.com/mozilla/pdf.js/issues/3260
-  // Last tested with version 6.0.4.
-  if (isSafari || isIOS) {
-    PDFJS.disableRange = true;
-    PDFJS.disableStream = true;
-  }
-})();
-
 // Provides document.currentScript support
 // Support: IE, Chrome<29.
 (function checkCurrentScript() {