PDF Viewer - Add keyboard shortcuts for rotation

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 cbdacca30e92bf4b9b966da0fdc70a341862d3a6..18b008da3d6ddb7c2d8eca4ebca3dd4f575f5c38 100644
--- a/chrome/browser/resources/pdf/pdf.js
+++ b/chrome/browser/resources/pdf/pdf.js
@@ -234,6 +234,16 @@ PDFViewer.prototype = {
           e.preventDefault();
         }
         return;
+      case 219:  // left bracket.
+        this.plugin_.postMessage({
+          type: 'rotateCounterclockwise',
+        });
+        return;
+      case 221:  // right bracket.
+        this.plugin_.postMessage({
+          type: 'rotateClockwise',
+        });
+        return;
     }
   },