Do RTL tabstrip transforms before animating tabs.

chrome/browser/ui/cocoa/tabs/tab_strip_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/tabs/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 1109 matching lines @@
       tabFrame.size.width = MAX(tabFrame.size.width, kMinActiveTabWidth);
 
     // If this is the first non-pinned tab, then add a bit of spacing between
     // this and the last pinned tab.
     if (!isPinned && isLastTabPinned) {
       offset += kLastPinnedTabSpacing;
       tabFrame.origin.x = offset;
     }
     isLastTabPinned = isPinned;
 
+    // Flip if in RTL mode.
+    tabFrame.origin.x =
+        FlipXInView(tabStripView_, tabFrame.size.width, tabFrame.origin.x);
+
     if (laidOutNonPinnedTabs > numberOfNonPinnedTabs) {
       // There is not enough space to fit this tab.
       tabFrame.size.width = 0;
       [self setFrame:tabFrame ofTabView:[tab view]];
       continue;
     }
 
     // Animate a new tab in by putting it below the horizon unless told to put
     // it in a specific location (i.e., from a drop).
     if (newTab && visible && animate) {
       if (NSEqualRects(droppedTabFrame_, NSZeroRect)) {
         [[tab view] setFrame:NSOffsetRect(tabFrame, 0, -NSHeight(tabFrame))];
       } else {
         [[tab view] setFrame:droppedTabFrame_];
         droppedTabFrame_ = NSZeroRect;
       }
     }
 
-    tabFrame.origin.x =
-        FlipXInView(tabStripView_, tabFrame.size.width, tabFrame.origin.x);
-
     // Check the frame by identifier to avoid redundant calls to animator.
     id frameTarget = visible && animate ? [[tab view] animator] : [tab view];
     NSValue* identifier = [NSValue valueWithPointer:[tab view]];
     NSValue* oldTargetValue = [targetFrames_ objectForKey:identifier];
     if (!oldTargetValue ||
         !NSEqualRects([oldTargetValue rectValue], tabFrame)) {
       // Redraw the tab once it moves to its final location. Because we're
       // using Core Animation, each tab caches its contents until told to
       // redraw. Without forcing a redraw at the end of the move, tabs will
       // display the wrong content when using a theme that creates transparent
@@ skipping 1247 matching lines @@
   for (int i = 0; i < tabStripModel_->count(); i++) {
     [self updateIconsForContents:tabStripModel_->GetWebContentsAt(i) atIndex:i];
   }
 }
 
 - (void)setVisualEffectsDisabledForFullscreen:(BOOL)fullscreen {
   [tabStripView_ setVisualEffectsDisabledForFullscreen:fullscreen];
 }
 
 @end