[Mac] Add testing code to expose an NSColor memory leak.

chrome/browser/cocoa/autocomplete_text_field_cell_unittest.mm

Index: chrome/browser/cocoa/autocomplete_text_field_cell_unittest.mm
diff --git a/chrome/browser/cocoa/autocomplete_text_field_cell_unittest.mm b/chrome/browser/cocoa/autocomplete_text_field_cell_unittest.mm
index fc101685138ff81b310fe35c5369522738b9bf37..0f6c8013cae4181b73e417a8793519dd32286292 100644
--- a/chrome/browser/cocoa/autocomplete_text_field_cell_unittest.mm
+++ b/chrome/browser/cocoa/autocomplete_text_field_cell_unittest.mm
@@ -17,10 +17,11 @@ class AutocompleteTextFieldCellTest : public PlatformTest {
   AutocompleteTextFieldCellTest() {
     // Make sure this is wide enough to play games with the cell
     // decorations.
-    NSRect frame = NSMakeRect(0, 0, 300, 30);
+    const NSRect frame = NSMakeRect(0, 0, 300, 30);
     view_.reset([[NSTextField alloc] initWithFrame:frame]);
     scoped_nsobject<AutocompleteTextFieldCell> cell(
         [[AutocompleteTextFieldCell alloc] initTextCell:@"Testing"]);
+    [cell setEditable:YES];
     [view_ setCell:cell.get()];
     [cocoa_helper_.contentView() addSubview:view_.get()];
   }
@@ -41,6 +42,11 @@ TEST_F(AutocompleteTextFieldCellTest, AddRemove) {
 TEST_F(AutocompleteTextFieldCellTest, Display) {
   [view_ display];
 
+  // Test focussed drawing.
+  cocoa_helper_.makeFirstResponder(view_);
+  [view_ display];
+  cocoa_helper_.clearFirstResponder();
+
   // Test display of various cell configurations.
   AutocompleteTextFieldCell* cell =
       static_cast<AutocompleteTextFieldCell*>([view_ cell]);