Mac: Make calling WebContents::WasShown/WasHidden the responsibility of the content layer

chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm

Index: chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
diff --git a/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm b/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
index 67f12778ef6851089ab58eb2ee7a5c069c756445..201d05f226b811b5f492e8b396e589efef7b2c72 100644
--- a/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
+++ b/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
@@ -679,7 +679,10 @@ NSImage* Overlay(NSImage* ground, NSImage* overlay, CGFloat alpha) {
     // ensureContentsVisible (see below) sets content size and autoresizing
     // properties.
     [newView setFrame:[oldView frame]];
-    [switchView_ replaceSubview:oldView with:newView];
+    // Remove the old view first, to ensure ConstrainedWindowSheets keyed to the
+    // old WebContents are removed before adding new ones.

[Avi (use Gerrit), 2016/02/29 17:27:23]

As a side note, this sounds like a limitation of the constrained window code
that should be fixed. :)

+    [oldView removeFromSuperview];
+    [switchView_ addSubview:newView];
   } else {
     [newView setFrame:[switchView_ bounds]];
     [switchView_ addSubview:newView];
@@ -1376,7 +1379,6 @@ NSImage* Overlay(NSImage* ground, NSImage* overlay, CGFloat alpha) {
       TabContentsController* oldController =
           [tabContentsArray_ objectAtIndex:oldIndex];
       [oldController willBecomeUnselectedTab];
-      oldContents->WasHidden();
     }
   }
 
@@ -1402,10 +1404,8 @@ NSImage* Overlay(NSImage* ground, NSImage* overlay, CGFloat alpha) {
   // Swap in the contents for the new tab.
   [self swapInTabAtIndex:modelIndex];
 
-  if (newContents) {
-    newContents->WasShown();
+  if (newContents)
     newContents->RestoreFocus();
-  }
 }
 
 - (void)tabSelectionChanged {