PDF: Add shortcut to toggle fit-to-{page,width}.

chrome/test/data/pdf/material_elements_test.js

Index: chrome/test/data/pdf/material_elements_test.js
diff --git a/chrome/test/data/pdf/material_elements_test.js b/chrome/test/data/pdf/material_elements_test.js
index 60bc2298c198133d161f5c11b541bc13ab9fa223..082e960925054f95416a7f75dbcf4a700f13b639 100644
--- a/chrome/test/data/pdf/material_elements_test.js
+++ b/chrome/test/data/pdf/material_elements_test.js
@@ -179,6 +179,18 @@ var tests = [
     MockInteractions.tap(fab);
     assertEvent('fit-to-page');
 
+    // Do the same as above, but with fitToggleFromHotKey().
+    zoomToolbar.fitToggleFromHotKey();
+    assertEvent('fit-to-width');
+    zoomToolbar.fitToggleFromHotKey();
+    assertEvent('fit-to-page');
+    zoomToolbar.fitToggleFromHotKey();
+    assertEvent('fit-to-width');
+
+    // Tap 4: Fire fit-to-page again.
+    MockInteractions.tap(fab);
+    assertEvent('fit-to-page');
+
     chrome.test.succeed();
   }
 ];