[Mac] Prevent omnibox text bg from drawing over decoration, focus ring.

chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_editor.mm

Index: chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_editor.mm
diff --git a/chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_editor.mm b/chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_editor.mm
index a8214d4425604dbd530206f7bfb07b08325878c4..6ba885e04741bd40c68c522c2f9f7110e6799b04 100644
--- a/chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_editor.mm
+++ b/chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_editor.mm
@@ -598,6 +598,20 @@ NSMenuItem* PasteAndGoMenuItemForObserver(
   [[FindPasteboard sharedInstance] setFindText:[selection string]];
 }
 
+- (BOOL)isOpaque {
+  // Even if you call -setDrawsBackground:NO, the background still gets drawn
+  // when editing. This is a problem because the left edge of the background
+  // overlaps the security decoration's hover rect. Return that the textview
+  // is transparent, and follow up below by disabling any background drawing.
+  // This will cause background drawing to fall through to the cell. See
+  // https://crbug.com/669870 .
+  return NO;
+}
+
+- (void)drawViewBackgroundInRect:(NSRect)aRect {
+  // See the comment in -isOpaque.
+}
+
 - (void)drawRect:(NSRect)rect {
   AutocompleteTextFieldObserver* observer = [self observer];
   if (observer)