[CRX] Show nicely formatted URL in omnibox

Before commit:
chrome-extension://EXTENSIONID/content/web/viewer.html?file=http%3A%2F%2Fexample.com%2Ffile.pdf

After commit:
chrome-extension://EXTENSIONID/http://example/file.pdf

Technical details:
- The extension's background page uses the webRequest API to intercept
  requests for <extension host>/<real path to pdf>, and redirect it to
  the viewer's URL.
- viewer.js uses history.replaceState to rewrite the URL, so that it's
  easier for users to recognize and copy-paste URLs.
- The fake paths /http:, /https:, /file:, etc. have been added to the
  web_accessible_resources section of the manifest file, in order to
  avoid seeing chrome-extension://invalid/ instead of the actual URL
  when using history back/forward to navigate from/to the PDF viewer.
- Since the relative path resolving doesn't work because relative URLs
  are inaccurate, a <base> tag has been added. This method has already
  been proven to work in the Firefox add-on.

Notes:
- This commit has been cherry-picked from crx-using-streams-api.
- Need to merge https://github.com/mozilla/pdf.js/pull/3582 to deal with
  a bug in Chrome <=30
- In Chrome, getting the contents of a FTP file is not possible, so
  there's no support for FTP files, even though the extension router
  recognizes the ftp: scheme.

web/viewer-snippet-chrome-extension.html

@@ -0,0 +1,5 @@
+<!-- This snippet is used in the Chrome extension, see Makefile -->
+<base href="/content/web/">
+<link rel="resource" type="application/l10n" href="locale/locale.properties">
+<script type="text/javascript" src="l10n.js"></script>
+<script type="text/javascript" src="../build/pdf.js"></script>

web/viewer.html

@@ -25,6 +25,9 @@ limitations under the License.
 
 <!--#if FIREFOX || MOZCENTRAL-->
 <!--#include viewer-snippet-firefox-extension.html-->
+<!--#endif-->
+<!--#if CHROME-->
+<!--#include viewer-snippet-chrome-extension.html-->
 <!--#endif-->
 
     <link rel="stylesheet" href="viewer.css"/>
@@ -53,7 +56,7 @@ limitations under the License.
     <script type="text/javascript">PDFJS.workerSrc = '../src/worker_loader.js';</script>
 <!--#endif-->
 
-<!--#if GENERIC || CHROME-->
+<!--#if GENERIC -->
 <!--#include viewer-snippet.html-->
 <!--#endif-->
 

web/viewer.js

@@ -670,15 +670,19 @@ var PDFView = {
   },
 
   /**
-   * For the firefox extension we prefix the full url on anchor links so they
-   * don't come up as resource:// urls and so open in new tab/window works.
-   * @param {String} anchor The anchor hash include the #.
+   * Prefix the full url on anchor links to make sure that links are resolved
+   * relative to the current URL instead of the one defined in <base href>.
+   * @param {String} anchor The anchor hash, including the #.
    */
   getAnchorUrl: function getAnchorUrl(anchor) {
-//#if !(FIREFOX || MOZCENTRAL)
+//#if !(FIREFOX || MOZCENTRAL || CHROME)
     return anchor;
 //#else
+//#if CHROME
+//  return location.href.split('#')[0] + anchor;
+//#else
 //  return this.url.split('#')[0] + anchor;
+//#endif
 //#endif
   },
 
@@ -1459,15 +1463,36 @@ var DocumentOutlineView = function documentOutlineView(outline) {
   }
 };
 
+//#if CHROME
+//(function rewriteUrlClosure() {
+//  // Run this code outside DOMContentLoaded to make sure that the URL
+//  // is rewritten as soon as possible.
+//  if (location.origin + '/' !== chrome.extension.getURL('/')) {
+//    DEFAULT_URL = window.location.href.split('#')[0];
+//  } else {
+//    var params = PDFView.parseQueryString(document.location.search.slice(1));
+//    DEFAULT_URL = params.file || DEFAULT_URL;
+//
+//    // Example: chrome-extension://.../http://example.com/file.pdf
+//    var humanReadableUrl = '/' + DEFAULT_URL + location.hash;
+//    history.replaceState(history.state, '', humanReadableUrl);
+//  }
+//})();
+//#endif
+
 document.addEventListener('DOMContentLoaded', function webViewerLoad(evt) {
   PDFView.initialize();
 
-//#if !(FIREFOX || MOZCENTRAL)
+//#if !(FIREFOX || MOZCENTRAL || CHROME)
   var params = PDFView.parseQueryString(document.location.search.substring(1));
   var file = params.file || DEFAULT_URL;
 //#else
+//#if CHROME
+//var file = DEFAULT_URL;
+//#else
 //var file = window.location.href.split('#')[0];
 //#endif
+//#endif
 
 //#if CHROME
 //if (location.protocol !== 'chrome-extension:') {