[Extensions Mac] Implement developer mode warning on mac

chrome/browser/ui/cocoa/extensions/browser_actions_container_view.mm

Index: chrome/browser/ui/cocoa/extensions/browser_actions_container_view.mm
diff --git a/chrome/browser/ui/cocoa/extensions/browser_actions_container_view.mm b/chrome/browser/ui/cocoa/extensions/browser_actions_container_view.mm
index ecd68752398300c86fdc5f14fdc5650bf067c349..d718eec153dc75ff690b75632600604f5e46e7bf 100644
--- a/chrome/browser/ui/cocoa/extensions/browser_actions_container_view.mm
+++ b/chrome/browser/ui/cocoa/extensions/browser_actions_container_view.mm
@@ -8,6 +8,8 @@
 
 #include "base/basictypes.h"
 #import "chrome/browser/ui/cocoa/view_id_util.h"
+#include "grit/theme_resources.h"
+#include "ui/base/cocoa/appkit_utils.h"
 
 NSString* const kBrowserActionGrippyDragStartedNotification =
     @"BrowserActionGrippyDragStartedNotification";
@@ -71,6 +73,15 @@ const CGFloat kMinimumContainerWidth = 3.0;
   [super dealloc];
 }
 
+- (void)drawRect:(NSRect)rect {
+  [super drawRect:rect];
+  if (isHighlighting_) {
+    ui::NinePartImageIds imageIds = IMAGE_GRID(IDR_DEVELOPER_MODE_HIGHLIGHT);
+    ui::DrawNinePartImage(
+        [self bounds], imageIds, NSCompositeSourceOver, 1.0, true);
+  }
+}
+
 - (void)setTrackingEnabled:(BOOL)enabled {
   if (enabled) {
     trackingArea_.reset(
@@ -88,6 +99,13 @@ const CGFloat kMinimumContainerWidth = 3.0;
   }
 }
 
+- (void)setIsHighlighting:(BOOL)isHighlighting {
+  if (isHighlighting != isHighlighting_) {
+    isHighlighting_ = isHighlighting;
+    [self setNeedsDisplay:YES];
+  }
+}
+
 - (void)setResizable:(BOOL)resizable {
   if (resizable == resizable_)
     return;