Updates Zoom bubble layout and adds +/- buttons

chrome/app/vector_icons/BUILD.gn

 # Copyright 2017 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("//build/util/branding.gni")
 import("//ui/vector_icons/vector_icons.gni")
 
 aggregate_vector_icons("chrome_vector_icons") {
   icon_directory = "."
 
@@ skipping 32 matching lines @@
     "folder_managed.1x.icon",
     "folder_managed.icon",
     "folder_supervised.1x.icon",
     "folder_supervised.icon",
     "globe.icon",
     "image.icon",
     "incognito.1x.icon",
     "incognito.icon",
     "laptop.icon",
     "lock.icon",
+    "minus.1x.icon",

[Evan Stade, 2017/04/27 17:29:38]

could you call this zoom_minus and zoom_plus? There are likely many places we
might use plus and minus icons in Chrome but their exact appearance might
differ. Plus this makes it immediately obvious how these are used for now, and
if we later want to reuse them for something not zoom related we can make that
switch easily.

(other icons with generic names here like "code" are copying the names on
go/icons)

[varkha, 2017/04/28 02:06:13]

Those are already taken (by magnifying glass icons). Since I based those on the
icons I've found on go/icons I will rename them to generic add / remove.

+    "minus.icon",
     "mixed_content.icon",
     "my_location.icon",
     "navigate_home.1x.icon",
     "navigate_home.icon",
     "navigate_reload.1x.icon",
     "navigate_reload.icon",
     "navigate_stop.1x.icon",
     "navigate_stop.icon",
     "overflow_chevron.1x.icon",
     "overflow_chevron.icon",
     "paintbrush.icon",
     "photo_camera.icon",
+    "plus.1x.icon",
+    "plus.icon",
     "remove_box.icon",
     "sad_tab.icon",
     "settings.icon",
     "smartphone.icon",
     "subresource_filter_active.icon",
     "supervisor_account.icon",
     "supervisor_account_circle.icon",
     "sync_problem.icon",
     "tab.icon",
     "tab_audio.1x.icon",
@@ skipping 39 matching lines @@
 source_set("vector_icons") {
   sources = get_target_outputs(":chrome_vector_icons")
   sources += [ "//ui/gfx/vector_icon_types.h" ]
 
   deps = [
     ":chrome_vector_icons",
     "//base",
     "//skia",
   ]
 }