Update Panel titlebar text and icon layout when resized on Mac.

chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm

Index: chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm
diff --git a/chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm b/chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm
index bc866b095deeccbecd3d05e0c013b2ae97202287..2cbab4d3c8bea0a8cfabad431d9feeca43804b55 100644
--- a/chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm
+++ b/chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm
@@ -194,7 +194,6 @@ static NSEvent* MakeMouseEvent(NSEventType type,
 
   // Update layout of controls in the titlebar.
   [self updateCloseButtonLayout];
-  [self updateIconAndTitleLayout];
 
   // Set autoresizing behavior: glued to edges on left, top and right.
   [self setAutoresizingMask:(NSViewMinYMargin | NSViewWidthSizable)];
@@ -204,8 +203,11 @@ static NSEvent* MakeMouseEvent(NSEventType type,
          selector:@selector(didChangeTheme:)
              name:kBrowserThemeDidChangeNotification
            object:nil];
-  // Register for various window focus changes, so we can update our custom
-  // titlebar appropriately.
+  [[NSNotificationCenter defaultCenter]
+      addObserver:self
+         selector:@selector(didChangeFrame:)
+             name:NSViewFrameDidChangeNotification
+           object:self];
   [[NSNotificationCenter defaultCenter]
       addObserver:self
          selector:@selector(didChangeMainWindow:)
@@ -300,6 +302,10 @@ static NSEvent* MakeMouseEvent(NSEventType type,
   [[closeButton_ cell] setHighlighted:NO];
 }
 
+- (void)didChangeFrame:(NSNotification*)notification {
+  [self updateIconAndTitleLayout];
+}
+
 - (void)didChangeTheme:(NSNotification*)notification {
   [self setNeedsDisplay:YES];
 }
@@ -411,6 +417,10 @@ static NSEvent* MakeMouseEvent(NSEventType type,
   return controller_;
 }
 
+- (NSTextField*)title {
+  return title_;
+}
+
 - (void)simulateCloseButtonClick {
   [[closeButton_ cell] performClick:closeButton_];
 }