Promote Apps Developer Tools in the chrome:extensions page

chrome/browser/resources/extensions/extensions.css

Index: chrome/browser/resources/extensions/extensions.css
diff --git a/chrome/browser/resources/extensions/extensions.css b/chrome/browser/resources/extensions/extensions.css
index 9e91ac7e845c7df7a785d0c65535528bfbdbddd0..101d27e6b4873018d5a9dad083f2e787fb15e167 100644
--- a/chrome/browser/resources/extensions/extensions.css
+++ b/chrome/browser/resources/extensions/extensions.css
@@ -41,6 +41,45 @@ html:not(.focus-outline-visible)
   white-space: nowrap;
 }
 
+#apps-developer-tools-promo {
+  -webkit-margin-before: 15px;
+  -webkit-padding-before: 5px;
+  align-items: center;
+  border-top: 1px solid #eee;
+  display: flex;
+  font-size: 13px;
+}
+
+#apps-developer-tools-promo img {
+  content: url(apps_developer_tools_promo_48.png);
+}
+
+#apps-developer-tools-promo-text,
+#apps-developer-tools-promo-link {
+  -webkit-margin-start: 5px;
+}
+
+#apps-developer-tools-promo-close-wrapper {
+  display: flex;
+  flex-grow: 1;
+  justify-content: flex-end;
+}
+
+#apps-developer-tools-promo .close-button {
+  background: url(chrome://theme/IDR_CLOSE_DIALOG) no-repeat center center;
+  height: 14px;
+  width: 14px;
+  z-index: 1;
+}
+
+#apps-developer-tools-promo .close-button:hover {
+  background-image: url(chrome://theme/IDR_CLOSE_DIALOG_H);
+}
+
+#apps-developer-tools-promo .close-button:active {
+  background-image: url(chrome://theme/IDR_CLOSE_DIALOG_P);
+}
+
 #extension-settings.dev-mode #dev-controls {
   -webkit-transition-duration: 250ms;
   height: 45px;
@@ -48,6 +87,10 @@ html:not(.focus-outline-visible)
   padding-bottom: 7px;
 }
 
+#extension-settings.dev-mode.adt-promo #dev-controls {
+  height: 105px;  /* Allow more height for the Apps Developer Tools promo. */
+}
+
 #dev-controls-spacer {
   -webkit-box-flex: 1;
 }
@@ -87,12 +130,12 @@ html:not(.focus-outline-visible)
 }
 
 #footer-section {
-  background: url('chrome://theme/IDR_WEBSTORE_ICON_32') no-repeat left center;
+  background: url(chrome://theme/IDR_WEBSTORE_ICON_32) no-repeat left center;
   font-size: 1.25em;
 }
 
 html[dir=rtl] #footer-section {
-  background: url('chrome://theme/IDR_WEBSTORE_ICON_32') no-repeat right center;
+  background: url(chrome://theme/IDR_WEBSTORE_ICON_32) no-repeat right center;
 }
 
 #footer-section > a {
@@ -317,7 +360,7 @@ html[dir='rtl'] #extension-settings .trash {
 }
 
 .profile-is-managed-banner .page-banner-text {
-  background-image: url('chrome://theme/IDR_WARNING');
+  background-image: url(chrome://theme/IDR_WARNING);
 }
 
 /* Sideload Wipeout */