viewer: use esbuild to bundle pdf viewer and worker

This improves maintainability:
1. no need to hardcode each script file in Android code
2. no need to symlink pdf.js and pdf.worker.js
3. adds sourcemaps in debug builds to help debug some pdf.js related
   issues

.eslintrc.json

@@ -30,11 +30,10 @@
         ]
     },
     "globals": {
-        "pdfjsLib": "readonly",
         "channel": "readonly"
     },
     "ignorePatterns": [
-        "pdf.js",
-        "pdf.worker.js"
+        "/app/src/*/assets/viewer",
+        "build/"
     ]
 }

.gitignore

@@ -7,3 +7,4 @@ keystore.properties
 /.idea
 /releases
 /node_modules
+/app/src/*/assets/viewer

app/src/main/java/app/grapheneos/pdfviewer/PdfViewer.java

@@ -309,7 +309,7 @@ public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceReque
                     return new WebResourceResponse("application/pdf", null, mInputStream);
                 }
 
-                if ("/viewer.html".equals(path)) {
+                if ("/viewer/index.html".equals(path)) {
                     final WebResourceResponse response = fromAsset("text/html", path);
                     HashMap<String, String> headers = new HashMap<>();
                     headers.put("Content-Security-Policy", CONTENT_SECURITY_POLICY);
@@ -319,11 +319,11 @@ public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceReque
                     return response;
                 }
 
-                if ("/viewer.css".equals(path)) {
+                if ("/viewer/main.css".equals(path)) {
                     return fromAsset("text/css", path);
                 }
 
-                if ("/viewer.js".equals(path) || "/pdf.js".equals(path) || "/pdf.worker.js".equals(path)) {
+                if ("/viewer/js/index.js".equals(path) || "/viewer/js/worker.js".equals(path)) {
                     return fromAsset("application/javascript", path);
                 }
 
@@ -520,7 +520,7 @@ private void loadPdf() {
         mDocumentState = 0;
         showSystemUi();
         invalidateOptionsMenu();
-        binding.webview.loadUrl("https://localhost/viewer.html");
+        binding.webview.loadUrl("https://localhost/viewer/index.html");
     }
 
     public void loadPdfWithPassword(final String password) {