[Mac] Implement WindowSizer::GetDefaultPopupOrigin()...

chrome/browser/window_sizer_mac.mm

Index: chrome/browser/window_sizer_mac.mm
===================================================================
--- chrome/browser/window_sizer_mac.mm	(revision 35456)
+++ chrome/browser/window_sizer_mac.mm	(working copy)
@@ -4,6 +4,9 @@
 
 #import <Cocoa/Cocoa.h>
 
+#include "chrome/browser/browser.h"
+#include "chrome/browser/browser_list.h"
+#include "chrome/browser/browser_window.h"
 #include "chrome/browser/window_sizer.h"
 
 // How much horizontal and vertical offset there is between newly
@@ -116,5 +119,26 @@
 
 // static
 gfx::Point WindowSizer::GetDefaultPopupOrigin(const gfx::Size& size) {
-  return gfx::Point(0, 0);
+  NSRect work_area = [[NSScreen mainScreen] visibleFrame];
+  NSRect main_area = [[[NSScreen screens] objectAtIndex:0] frame];
+  NSPoint corner = NSMakePoint(NSMinX(work_area), NSMaxY(work_area));
+
+  if (Browser* b = BrowserList::GetLastActive()) {
+    NSWindow* window = b->window()->GetNativeHandle();
+    NSRect window_frame = [window frame];
+
+    // Limit to not overflow the work area right and bottom edges.
+    NSPoint limit = NSMakePoint(
+        std::min(NSMinX(window_frame) + kWindowTilePixels,
+                 NSMaxX(work_area) - size.width()),
+        std::max(NSMaxY(window_frame) - kWindowTilePixels,
+                 NSMinY(work_area) + size.height()));
+
+    // Adjust corner to now overflow the work area left and top edges, so
+    // that if a popup does not fit the title-bar is remains visible.
+    corner = NSMakePoint(std::max(corner.x, limit.x),
+                         std::min(corner.y, limit.y));
+  }
+
+  return gfx::Point(corner.x, NSHeight(main_area) - corner.y);
 }