Don't animate the download shelf when entering/exiting fullscreen.

chrome/browser/ui/cocoa/download/download_shelf_controller.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/download/download_shelf_controller.h"
 
 #include <stddef.h>
 
 #include "base/mac/bundle_locations.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 209 matching lines @@
   }
 }
 
 - (void)downloadWasOpened:(DownloadItemController*)item_controller {
   // This should only be called on the main thead.
   DCHECK([NSThread isMainThread]);
   [self maybeAutoCloseAfterDelay];
 }
 
 - (void)showDownloadShelf:(BOOL)show
-             isUserAction:(BOOL)isUserAction {
+             isUserAction:(BOOL)isUserAction
+                  animate:(BOOL)animate {
   [self cancelAutoClose];
   shouldCloseOnMouseExit_ = NO;
 
   if ([self isVisible] == show)
     return;
 
   if (!show) {
     int numInProgress = 0;
     for (NSUInteger i = 0; i < [downloadItemControllers_ count]; ++i) {
       DownloadItem* item = [[downloadItemControllers_ objectAtIndex:i]download];
       if (item->GetState() == DownloadItem::IN_PROGRESS)
         ++numInProgress;
     }
     RecordDownloadShelfClose(
         [downloadItemControllers_ count], numInProgress, !isUserAction);
   }
 
   // Animate the shelf out, but not in.
   // TODO(rohitrao): We do not animate on the way in because Cocoa is already
   // doing a lot of work to set up the download arrow animation.  I've chosen to
   // do no animation over janky animation.  Find a way to make animating in
   // smoother.

[Nico, 2017/02/17 15:53:46]

maybe we can reconsider this now that machines are 5 years faster?

[Sidney San Martín, 2017/02/17 16:07:08]

I am 100% planning to do this when I get back to my downloads bar rework (soon).

   AnimatableView* view = [self animatableView];
-  if (show) {
-    [view setHeight:maxShelfHeight_];
-    [view setHidden:NO];
+  if (animate && !show) {
+    [view animateToNewHeight:0 duration:kDownloadShelfCloseDuration];
   } else {
-    [view animateToNewHeight:0 duration:kDownloadShelfCloseDuration];
+    [view setHeight:show ? maxShelfHeight_ : 0];
+    [view setHidden:!show];
   }
 
   barIsVisible_ = show;
   [self updateCloseButton];
 }
 
 - (DownloadShelf*)bridge {
   return bridge_.get();
 }
 
@@ skipping 237 matching lines @@
   }
 
   // Set the tracking off to create a new tracking area for the control.
   // When changing the bounds/frame on a HoverButton, the tracking isn't updated
   // correctly, it needs to be turned off and back on.
   [hoverCloseButton_ setTrackingEnabled:NO];
   [hoverCloseButton_ setFrame:bounds];
   [hoverCloseButton_ setTrackingEnabled:YES];
 }
 @end