mac: Fix bug where finder window extends past bottom of screen.

chrome/browser/ui/cocoa/browser_window_controller_private.mm

Index: chrome/browser/ui/cocoa/browser_window_controller_private.mm
diff --git a/chrome/browser/ui/cocoa/browser_window_controller_private.mm b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
index 3874f2005a146a1393b43bd605710d18c9cbd265..ba6f02b2475c1d60bee94b3d5bc9978a987c486e 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller_private.mm
+++ b/chrome/browser/ui/cocoa/browser_window_controller_private.mm
@@ -204,26 +204,44 @@ willPositionSheet:(NSWindow*)sheet
   //    the sheet below the bookmark bar.
   //  - If the bookmark bar is currently animating, position the sheet according
   //    to where the bar will be when the animation ends.
+  CGFloat desiredY = defaultSheetRect.origin.y;

[Robert Sesek, 2014/10/27 15:41:22]

naming: desiredY -> defaultSheetY

[erikchen, 2014/10/27 23:18:13]

Done.

   switch ([bookmarkBarController_ currentState]) {
     case BookmarkBar::SHOW: {
       NSRect bookmarkBarFrame = [[bookmarkBarController_ view] frame];
-      defaultSheetRect.origin.y = bookmarkBarFrame.origin.y;
+      desiredY = bookmarkBarFrame.origin.y;
       break;
     }
     case BookmarkBar::HIDDEN:
     case BookmarkBar::DETACHED: {
       if ([self hasToolbar]) {
         NSRect toolbarFrame = [[toolbarController_ view] frame];
-        defaultSheetRect.origin.y = toolbarFrame.origin.y;
+        desiredY = toolbarFrame.origin.y;
       } else {
         // The toolbar is not shown in application mode. The sheet should be
         // located at the top of the window, under the title of the window.
-        defaultSheetRect.origin.y = NSHeight([[window contentView] frame]) -
-                                    defaultSheetRect.size.height;
+        desiredY = NSHeight([[window contentView] frame]) -
+                   defaultSheetRect.size.height;
       }
       break;
     }
   }
+
+  // AppKit may shift the window up to fit the sheet on screen, but it will
+  // never adjust the height of the sheet, or the origin of the sheet relative
+  // to the window. Adjust the origin to prevent sheets from extending past the
+  // bottom of the screen.
+
+  // Don't allow the sheet to extend past the bottom of the window. This logic
+  // intentionally ignores the size of the screens, since the window might span
+  // multiple screens, and AppKit may reposition the window.
+  CGFloat sheetHeight = NSHeight([sheet frame]);
+  desiredY = std::max(desiredY, sheetHeight);
+
+  // It doesn't make sense to provide a Y higher than the height of the window.
+  CGFloat windowHeight = NSHeight([window frame]);
+  desiredY = std::min(desiredY, windowHeight);
+
+  defaultSheetRect.origin.y = desiredY;
   return defaultSheetRect;
 }