Fix inconsistent spacing and trailing commas in objects in web/ files, so we can enable the comma-dangle and object-curly-spacing ESLint rules later on

http://eslint.org/docs/rules/comma-dangle
http://eslint.org/docs/rules/object-curly-spacing

Given that we currently have quite inconsistent object formatting, fixing this in in *one* big patch probably wouldn't be feasible (since I cannot imagine anyone wanting to review that); hence I've opted to try and do this piecewise instead.

*Please note:* This patch was created automatically, using the ESLint `--fix` command line option. In a couple of places this caused lines to become too long, and I've fixed those manually; please refer to the interdiff below for the only hand-edits in this patch.

```diff
diff --git a/web/pdf_thumbnail_view.js b/web/pdf_thumbnail_view.js
index 002dbf29..1de4e530 100644
--- a/web/pdf_thumbnail_view.js
+++ b/web/pdf_thumbnail_view.js
@@ -420,8 +420,8 @@ var PDFThumbnailView = (function PDFThumbnailViewClosure() {
     setPageLabel: function PDFThumbnailView_setPageLabel(label) {
       this.pageLabel = (typeof label === 'string' ? label : null);

-      this.l10n.get('thumb_page_title', { page: this.pageId, }, 'Page {{page}}').
-          then((msg) => {
+      this.l10n.get('thumb_page_title', { page: this.pageId, },
+                    'Page {{page}}').then((msg) => {
         this.anchor.title = msg;
       });

diff --git a/web/secondary_toolbar.js b/web/secondary_toolbar.js
index 160e0410..6495fc5e 100644
--- a/web/secondary_toolbar.js
+++ b/web/secondary_toolbar.js
@@ -65,7 +65,8 @@ class SecondaryToolbar {
       { element: options.printButton, eventName: 'print', close: true, },
       { element: options.downloadButton, eventName: 'download', close: true, },
       { element: options.viewBookmarkButton, eventName: null, close: true, },
-      { element: options.firstPageButton, eventName: 'firstpage', close: true, },
+      { element: options.firstPageButton, eventName: 'firstpage',
+        close: true, },
       { element: options.lastPageButton, eventName: 'lastpage', close: true, },
       { element: options.pageRotateCwButton, eventName: 'rotatecw',
         close: false, },
@@ -76,7 +77,7 @@ class SecondaryToolbar {
       { element: options.cursorHandToolButton, eventName: 'switchcursortool',
         eventDetails: { tool: CursorTool.HAND, }, close: true, },
       { element: options.documentPropertiesButton,
-        eventName: 'documentproperties', close: true, }
+        eventName: 'documentproperties', close: true, },
     ];
     this.items = {
       firstPage: options.firstPageButton,
```

web/ui_utils.js

@@ -51,7 +51,7 @@ var NullL10n = {
 
   translate(element) {
     return Promise.resolve();
-  }
+  },
 };
 
 /**
@@ -125,7 +125,7 @@ function getOutputScale(ctx) {
   return {
     sx: pixelRatio,
     sy: pixelRatio,
-    scaled: pixelRatio !== 1
+    scaled: pixelRatio !== 1,
   };
 }
 
@@ -200,7 +200,7 @@ function watchScroll(viewAreaElement, callback) {
   var state = {
     down: true,
     lastY: viewAreaElement.scrollTop,
-    _eventHandler: debounceScroll
+    _eventHandler: debounceScroll,
   };
 
   var rAF = null;
@@ -350,7 +350,7 @@ function getVisibleElements(scrollEl, views, sortByVisibility) {
       x: currentWidth,
       y: currentHeight,
       view,
-      percent: percentHeight
+      percent: percentHeight,
     });
   }
 
@@ -508,7 +508,7 @@ var EventBus = (function EventBusClosure() {
       eventListeners.slice(0).forEach(function (listener) {
         listener.apply(null, args);
       });
-    }
+    },
   };
   return EventBus;
 })();
@@ -589,7 +589,7 @@ var ProgressBar = (function ProgressBarClosure() {
       this.visible = true;
       document.body.classList.add('loadingInProgress');
       this.bar.classList.remove('hidden');
-    }
+    },
   };
 
   return ProgressBar;