Refactor browser window zoom handling and enable zoom icon on all platforms.

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

Index: chrome/browser/ui/cocoa/location_bar/zoom_decoration.mm
diff --git a/chrome/browser/ui/cocoa/location_bar/zoom_decoration.mm b/chrome/browser/ui/cocoa/location_bar/zoom_decoration.mm
new file mode 100644
index 0000000000000000000000000000000000000000..f9de6fc251e89f2a613b2f8830d1e8ae03585cbf
--- /dev/null
+++ b/chrome/browser/ui/cocoa/location_bar/zoom_decoration.mm
@@ -0,0 +1,43 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "chrome/browser/ui/cocoa/location_bar/zoom_decoration.h"
+
+#include "base/string_number_conversions.h"
+#include "chrome/app/chrome_command_ids.h"
+#import "chrome/browser/ui/cocoa/omnibox/omnibox_view_mac.h"
+#include "chrome/browser/ui/toolbar/toolbar_model.h"
+#include "chrome/browser/ui/zoom/zoom_controller.h"
+#include "grit/generated_resources.h"
+#include "ui/base/l10n/l10n_util_mac.h"
+
+ZoomDecoration::ZoomDecoration(ToolbarModel* toolbar_model)
+    : toolbar_model_(toolbar_model) {
+  Update(NULL);
+}
+
+ZoomDecoration::~ZoomDecoration() {
+}
+
+void ZoomDecoration::Update(ZoomController* zoom_controller) {
+  if (!zoom_controller || zoom_controller->IsAtDefaultZoom() ||
+      toolbar_model_->input_in_progress()) {
+    // TODO(dbeam): hide zoom bubble when it exists.
+    SetVisible(false);
+    return;
+  }
+
+  SetImage(OmniboxViewMac::ImageForResource(
+      zoom_controller->GetResourceForZoomLevel()));
+
+  int zoom_percent = zoom_controller->zoom_percent();
+  tooltip_.reset([l10n_util::GetNSStringFWithFixup(
+      IDS_TOOLTIP_ZOOM, base::IntToString16(zoom_percent)) retain]);

[Scott Hess - ex-Googler, 2012/08/16 04:52:58]

There's a lot going on in this line, I think it might benefit from some
temporary variables to help document things.

[Dan Beam, 2012/08/16 08:55:03]

Done.

+
+  SetVisible(true);
+}
+
+NSString* ZoomDecoration::GetToolTip() {
+  return tooltip_.get();
+}