Fix tab dragging to always hide the new tab button while dragging a tab or targeting an existing window. Makes things much nicer.

BUG=14923, 14925, 15667
TEST=dragging tabs in and out of windows, and within windows. Make sure new tab button goes away when it should and always comes back.
Review URL: http://codereview.chromium.org/160345

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@22092 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 63 insertions, 22 deletions

diff --git a/chrome/browser/cocoa/browser_window_controller.mm b/chrome/browser/cocoa/browser_window_controller.mm
index d8c801b..76dcd09 100644
--- a/chrome/browser/cocoa/browser_window_controller.mm
+++ b/chrome/browser/cocoa/browser_window_controller.mm
@@ -438,7 +438,7 @@ willPositionSheet:(NSWindow*)sheet
           break;
       }
 
-      // If the item is toggleable, find it's toggle state and
+      // If the item is toggleable, find its toggle state and
       // try to update it.  This is a little awkward, but the alternative is
       // to check after a commandDispatch, which seems worse.
       [self updateToggleStateWithTag:tag forItem:item];
@@ -663,17 +663,23 @@ willPositionSheet:(NSWindow*)sheet
 - (void)insertPlaceholderForTab:(TabView*)tab
                           frame:(NSRect)frame
                       yStretchiness:(CGFloat)yStretchiness {
+  [super insertPlaceholderForTab:tab frame:frame yStretchiness:yStretchiness];
   [tabStripController_ insertPlaceholderForTab:tab
                                          frame:frame
                                  yStretchiness:yStretchiness];
 }
 
 - (void)removePlaceholder {
+  [super removePlaceholder];
   [tabStripController_ insertPlaceholderForTab:nil
                                          frame:NSZeroRect
                                  yStretchiness:0];
 }
 
+- (void)showNewTabButton:(BOOL)show {
+  [tabStripController_ showNewTabButton:show];
+}
+
 - (BOOL)isBookmarkBarVisible {
   return [[toolbarController_ bookmarkBarController] isBookmarkBarVisible];
 
diff --git a/chrome/browser/cocoa/tab_strip_controller.h b/chrome/browser/cocoa/tab_strip_controller.h
index 46924ef..68c7ce4 100644
--- a/chrome/browser/cocoa/tab_strip_controller.h
+++ b/chrome/browser/cocoa/tab_strip_controller.h
@@ -57,6 +57,8 @@ class ToolbarModel;
   // aren't coalesced, so we store frames to avoid redundant calls.
   scoped_nsobject<NSMutableDictionary> targetFrames_;
   NSRect newTabTargetFrame_;
+  // If YES, do not show the new tab button during layout.
+  BOOL forceNewTabButtonHidden_;
 
   // Width available for resizing the tabs (doesn't include the new tab
   // button). Used to restrict the available width when closing many tabs at
@@ -107,6 +109,10 @@ class ToolbarModel;
                           frame:(NSRect)frame
                   yStretchiness:(CGFloat)yStretchiness;
 
+// Show or hide the new tab button. The button is hidden immediately, but
+// waits until the next call to |-layoutTabs| to show it again.
+- (void)showNewTabButton:(BOOL)show;
+
 // Force the tabs to rearrange themselves to reflect the current model.
 - (void)layoutTabs;
 
diff --git a/chrome/browser/cocoa/tab_strip_controller.mm b/chrome/browser/cocoa/tab_strip_controller.mm
index a15244f..96a822b 100644
--- a/chrome/browser/cocoa/tab_strip_controller.mm
+++ b/chrome/browser/cocoa/tab_strip_controller.mm
@@ -225,6 +225,12 @@ static const float kUseFullAvailableWidth = -1.0;
   [self layoutTabs];
 }
 
+- (void)showNewTabButton:(BOOL)show {
+  forceNewTabButtonHidden_ = show ? NO : YES;
+  if (forceNewTabButtonHidden_)
+    [newTabButton_ setHidden:YES];
+}
+
 // Lay out all tabs in the order of their TabContentsControllers, which matches
 // the ordering in the TabStripModel. This call isn't that expensive, though
 // it is O(n) in the number of tabs. Tabs will animate to their new position
@@ -358,23 +364,29 @@ static const float kUseFullAvailableWidth = -1.0;
     i++;
   }
 
-  NSRect newTabNewFrame = [newTabButton_ frame];
-  if ([self useFullWidthForLayout])
-    newTabNewFrame.origin =
-        NSMakePoint(MIN(availableWidth, offset + kNewTabButtonOffset), 0);
-  else
-    newTabNewFrame.origin = NSMakePoint(offset + kNewTabButtonOffset, 0);
-  newTabNewFrame.origin.x = MAX(newTabNewFrame.origin.x,
-                                NSMaxX(placeholderFrame_));
-  if (i > 0 && [newTabButton_ isHidden]) {
-    id target = animate ? [newTabButton_ animator] : newTabButton_;
-    [target setHidden:NO];
-  }
+  // Hide the new tab button if we're explicitly told to. It may already
+  // be hidden, doing it again doesn't hurt.
+  if (forceNewTabButtonHidden_) {
+    [newTabButton_ setHidden:YES];
+  } else {
+    NSRect newTabNewFrame = [newTabButton_ frame];
+    if ([self useFullWidthForLayout])
+      newTabNewFrame.origin =
+          NSMakePoint(MIN(availableWidth, offset + kNewTabButtonOffset), 0);
+    else
+      newTabNewFrame.origin = NSMakePoint(offset + kNewTabButtonOffset, 0);
+    newTabNewFrame.origin.x = MAX(newTabNewFrame.origin.x,
+                                  NSMaxX(placeholderFrame_));
+    if (i > 0 && [newTabButton_ isHidden]) {
+      id target = animate ? [newTabButton_ animator] : newTabButton_;
+      [target setHidden:NO];
+    }
 
-  if (!NSEqualRects(newTabTargetFrame_, newTabNewFrame)) {
-    [newTabButton_ setFrame:newTabNewFrame];
-    newTabTargetFrame_ = newTabNewFrame;
-    // Move the new tab button into place.
+    if (!NSEqualRects(newTabTargetFrame_, newTabNewFrame)) {
+      [newTabButton_ setFrame:newTabNewFrame];
+      newTabTargetFrame_ = newTabNewFrame;
+      // Move the new tab button into place.
+    }
   }
 
   [NSAnimationContext endGrouping];
diff --git a/chrome/browser/cocoa/tab_view.mm b/chrome/browser/cocoa/tab_view.mm
index a8d9fb5..4036b18 100644
--- a/chrome/browser/cocoa/tab_view.mm
+++ b/chrome/browser/cocoa/tab_view.mm
@@ -251,6 +251,8 @@ static const double kDragStartDistance = 3.0;
     [dragWindow_ makeMainWindow];
     [draggedController_ showOverlay];
     dragOverlay_ = [draggedController_ overlayWindow];
+    // Force the new tab button to be hidden. We'll reset it on mouse up.
+    [draggedController_ showNewTabButton:NO];
     //if (![targets count])
     //  [dragOverlay_ setHasShadow:NO];
     if (!isTheOnlyTab_) {
@@ -346,6 +348,11 @@ static const double kDragStartDistance = 3.0;
   // The drag/click is done. If the user dragged the mouse, finalize the drag
   // and clean up.
 
+  // We are now free to re-display the new tab button in the window we're
+  // dragging. It will show when the next call to -layoutTabs (which happens
+  // indrectly by several of the calls below, such as removing the placeholder).
+  [draggedController_ showNewTabButton:YES];
+
   if (draggingWithinTabStrip_) {
     if (tabWasDragged_) {
       // Move tab to new location.
@@ -370,7 +377,6 @@ static const double kDragStartDistance = 3.0;
 
     [[draggedController_ window] setLevel:NSNormalWindowLevel];
     [draggedController_ removePlaceholder];
-    [draggedController_ layoutTabs];
   }
   [sourceController_ removePlaceholder];
   chromeIsVisible_ = YES;
diff --git a/chrome/browser/cocoa/tab_window_controller.h b/chrome/browser/cocoa/tab_window_controller.h
index 256732d..46928bd 100644
--- a/chrome/browser/cocoa/tab_window_controller.h
+++ b/chrome/browser/cocoa/tab_window_controller.h
@@ -54,14 +54,22 @@
 // new window will be the same size as this window.
 - (TabWindowController*)detachTabToNewWindow:(TabView*)tabView;
 
-// Make room in the tab strip for |tab| at the given x coordinate.
+// Make room in the tab strip for |tab| at the given x coordinate. Will hide the
+// new tab button while there's a placeholder. Subclasses need to call the
+// superclass implementation.
 - (void)insertPlaceholderForTab:(TabView*)tab
                           frame:(NSRect)frame
                   yStretchiness:(CGFloat)yStretchiness;
 
-// Removes the placeholder installed by |-insertPlaceholderForTab:atLocation:|.
+// Removes the placeholder installed by |-insertPlaceholderForTab:atLocation:|
+// and restores the new tab button. Subclasses need to call the superclass
+// implementation.
 - (void)removePlaceholder;
 
+// Show or hide the new tab button. The button is hidden immediately, but
+// waits until the next call to |-layoutTabs| to show it again.
+- (void)showNewTabButton:(BOOL)show;
+
 // Called to check if the receiver can receive dragged tabs from
 // source.  Return YES if so.  The default implementation returns NO.
 - (BOOL)canReceiveFrom:(TabWindowController*)source;
diff --git a/chrome/browser/cocoa/tab_window_controller.mm b/chrome/browser/cocoa/tab_window_controller.mm
index a1a308c..34417a0 100644
--- a/chrome/browser/cocoa/tab_window_controller.mm
+++ b/chrome/browser/cocoa/tab_window_controller.mm
@@ -141,11 +141,14 @@
 - (void)insertPlaceholderForTab:(TabView*)tab
                           frame:(NSRect)frame
                   yStretchiness:(CGFloat)yStretchiness {
-  // subclass must implement
-  NOTIMPLEMENTED();
+  [self showNewTabButton:NO];
 }
 
 - (void)removePlaceholder {
+  [self showNewTabButton:YES];
+}
+
+- (void)showNewTabButton:(BOOL)show {
   // subclass must implement
   NOTIMPLEMENTED();
 }