Handle the keyboard event for ctrl+a inside pdf.js instead of out_of_process_pdf.cc

chrome/browser/resources/pdf/pdf.js

Index: chrome/browser/resources/pdf/pdf.js
diff --git a/chrome/browser/resources/pdf/pdf.js b/chrome/browser/resources/pdf/pdf.js
index 0616c8df40ab1d66ea0ae1a68b962736a9fa4c32..2b22e600f5872bf26e2d67c2844d597218b79244 100644
--- a/chrome/browser/resources/pdf/pdf.js
+++ b/chrome/browser/resources/pdf/pdf.js
@@ -218,6 +218,13 @@ PDFViewer.prototype = {
           this.viewport.position = position;
         }
         return;
+      case 65:  // a key.
+        if (e.ctrlKey || e.metaKey) {
+          this.plugin_.postMessage({
+            type: 'selectAll',
+          });
+        }
+        return;
       case 83:  // s key.
         if (e.ctrlKey || e.metaKey) {
           // Simulate a click on the button so that the <a download ...>