pdf: Warn user when closing if they have made annotations but not saved

Bug: 902646, 933205
Change-Id: I7ddb3da8ac6131532896f886a03451351b3780aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1482356
Commit-Queue: dstockwell <dstockwell@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#637542}

chrome/browser/resources/pdf/elements/viewer-ink-host/viewer-ink-host.js

@@ -171,8 +171,10 @@ Polymer({
     this.activePointer_ = null;
     if (!this.pointerGesture_) {
       this.dispatchPointerEvent_(e);
-      // If the stroke was not cancelled, record metrics.
+      // If the stroke was not cancelled (type == pointercanel),
+      // notify about mutation and record metrics.
       if (e.type == 'pointerup') {
+        this.dispatchEvent(new CustomEvent('stroke-added'));
         if (e.pointerType == 'mouse') {
           PDFMetrics.record(PDFMetrics.UserAction.ANNOTATE_STROKE_DEVICE_MOUSE);
         } else if (e.pointerType == 'pen') {

chrome/browser/resources/pdf/pdf_viewer.js

@@ -1187,6 +1187,9 @@ PDFViewer.prototype = {
           entry.createWriter(writer => {
             writer.write(
                 new Blob([result.dataToSave], {type: 'application/pdf'}));
+            // Unblock closing the window now that the user has saved
+            // successfully.
+            chrome.mimeHandlerPrivate.setShowBeforeUnloadDialog(false);
           });
         });
 
@@ -1225,6 +1228,11 @@ PDFViewer.prototype = {
     this.currentController_.rotateCounterclockwise();
     this.updateAnnotationAvailable_();
   },
+
+  setHasUnsavedChanges: function() {
+    // Warn the user if they attempt to close the window without saving.
+    chrome.mimeHandlerPrivate.setShowBeforeUnloadDialog(true);
+  },
 };
 
 /** @abstract */
@@ -1356,6 +1364,9 @@ class InkController extends ContentController {
       this.inkHost_ = document.createElement('viewer-ink-host');
       $('content').appendChild(this.inkHost_);
       this.inkHost_.viewport = this.viewport_;
+      this.inkHost_.addEventListener('stroke-added', e => {
+        this.viewer_.setHasUnsavedChanges();
+      });
     }
     return this.inkHost_.load(filename, data);
   }