Mac: Only show one per-tab sheet at a time per tab.

chrome/browser/cocoa/tab_strip_controller.mm

 // Copyright (c) 2009 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/cocoa/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <limits>
 
@@ skipping 352 matching lines @@
   } else {
     [switchView_ addSubview:newView];
   }
 
   // Make sure the new tabs's sheets are visible (necessary when a background
   // tab opened a sheet while it was in the background and now becomes active).
   TabContents* newTab = tabModel_->GetTabContentsAt(modelIndex);
   DCHECK(newTab);
   if (newTab) {
     TabContents::ConstrainedWindowList::iterator it, end;
+    it = newTab->constrained_window_begin();
     end = newTab->constrained_window_end();
-    NSWindowController* controller = [[newView window] windowController];
-    DCHECK([controller isKindOfClass:[BrowserWindowController class]]);
 
-    for (it = newTab->constrained_window_begin(); it != end; ++it) {
+    // GTMWindowSheetController supports only one sheet at a time.
+    if (it != end) {
+      NSWindowController* controller = [[newView window] windowController];
+      DCHECK([controller isKindOfClass:[BrowserWindowController class]]);
       ConstrainedWindow* constrainedWindow = *it;
       static_cast<ConstrainedWindowMac*>(constrainedWindow)->Realize(
           static_cast<BrowserWindowController*>(controller));
     }
   }
 
   // Tell per-tab sheet manager about currently selected tab.
   if (sheetController_.get()) {
     [sheetController_ setActiveView:newView];
   }
@@ skipping 897 matching lines @@
   // Raise window...
   [[switchView_ window] makeKeyAndOrderFront:self];
 
   // ...and raise a tab with a sheet.
   NSInteger index = [self modelIndexForContentsView:view];
   DCHECK(index >= 0);
   if (index >= 0)
     tabModel_->SelectTabContentsAt(index, false /* not a user gesture */);
 }
 
-- (void)attachConstrainedWindow:(ConstrainedWindowMac*)window {
+- (BOOL)attachConstrainedWindow:(ConstrainedWindowMac*)window {
   // TODO(thakis, avi): Figure out how to make this work when tabs are dragged
   // out or if fullscreen mode is toggled.
 
   // View hierarchy of the contents view:
   // NSView  -- switchView, same for all tabs
   // +-  NSView  -- TabContentsController's view
   //     +- NSBox
   //        +- TabContentsViewCocoa
   // We use the TabContentsController's view in |swapInTabAtIndex|, so we have
   // to pass it to the sheet controller here.
   NSView* tabContentsView =
       [[window->owner()->GetNativeView() superview] superview];
-  window->delegate()->RunSheet([self sheetController], tabContentsView);
 
   // TODO(avi, thakis): GTMWindowSheetController has no api to move tabsheets
   // between windows. Until then, we have to prevent having to move a tabsheet
   // between windows, e.g. no tearing off of tabs.
   NSInteger modelIndex = [self modelIndexForContentsView:tabContentsView];
   NSInteger index = [self indexFromModelIndex:modelIndex];
   BrowserWindowController* controller =
       (BrowserWindowController*)[[switchView_ window] windowController];
   DCHECK(controller != nil);
   DCHECK(index >= 0);
   if (index >= 0) {
-    [controller setTab:[self viewAtIndex:index] isDraggable:NO];
+    NSView* tab = [self viewAtIndex:index];
+    [controller setTab:tab isDraggable:NO];
+
+    std::deque<ConstrainedWindowMac*>& windows = constrainedWindows_[tab];
+    std::deque<ConstrainedWindowMac*>::iterator it =
+        find(windows.begin(), windows.end(), window);
+    if (it == windows.end())
+      constrainedWindows_[tab].push_back(window);
+
+    if (constrainedWindows_[tab].size() == 1) {
+      [controller setTab:tab isDraggable:NO];
+      window->SetVisible();
+      window->delegate()->RunSheet([self sheetController], tabContentsView);
+      return YES;
+    }
   }
+  return NO;
 }
 
 - (void)removeConstrainedWindow:(ConstrainedWindowMac*)window {
   NSView* tabContentsView =
       [[window->owner()->GetNativeView() superview] superview];
 
   // TODO(avi, thakis): GTMWindowSheetController has no api to move tabsheets
   // between windows. Until then, we have to prevent having to move a tabsheet
   // between windows, e.g. no tearing off of tabs.
   NSInteger modelIndex = [self modelIndexForContentsView:tabContentsView];
   NSInteger index = [self indexFromModelIndex:modelIndex];
   BrowserWindowController* controller =
       (BrowserWindowController*)[[switchView_ window] windowController];
   DCHECK(index >= 0);
   if (index >= 0) {
-    [controller setTab:[self viewAtIndex:index] isDraggable:YES];
+    NSView* tab = [self viewAtIndex:index];
+
+    std::deque<ConstrainedWindowMac*>& windows = constrainedWindows_[tab];
+    std::deque<ConstrainedWindowMac*>::iterator it =
+        find(windows.begin(), windows.end(), window);
+    DCHECK(it != windows.end());
+
+    bool removedVisibleSheet = it == windows.begin();
+
+    if (it != windows.end())
+      windows.erase(it);
+
+    if (windows.size() == 0) {
+      [controller setTab:tab isDraggable:YES];
+      constrainedWindows_.erase(tab);
+    } else if (removedVisibleSheet && tab == [self selectedTabView]) {
+      // Show next sheet
+      NSWindowController* controller = [[tab window] windowController];
+      DCHECK([controller isKindOfClass:[BrowserWindowController class]]);
+      windows.front()->Realize(
+          static_cast<BrowserWindowController*>(controller));
+    }
   }
 }
 
 @end