Add default fonts for extensions.

This CL applies the default system font style to extension pages.
Extensions that specify their own fonts will still override these styles. 

BUG=141703, 395319

Review URL: https://codereview.chromium.org/400343002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284597 0039d316-1c4b-4281-b951-d872f2087c98

extensions/renderer/dispatcher.cc

@@ -325,20 +325,31 @@ void Dispatcher::WillReleaseScriptContext(
 }
 
 void Dispatcher::DidCreateDocumentElement(blink::WebFrame* frame) {
-  if (IsWithinPlatformApp()) {
-    // WebKit doesn't let us define an additional user agent stylesheet, so we
-    // insert the default platform app stylesheet into all documents that are
-    // loaded in each app.
+  // Note: use GetEffectiveDocumentURL not just frame->document()->url()
+  // so that this also injects the stylesheet on about:blank frames that
+  // are hosted in the extension process.
+  GURL effective_document_url = ScriptContext::GetEffectiveDocumentURL(
+      frame, frame->document().url(), true /* match_about_blank */);
+  const Extension* extension =
+      extensions_.GetExtensionOrAppByURL(effective_document_url);
+
+  if (extension &&
+      (extension->is_extension() || extension->is_platform_app())) {
+    int resource_id =
+        extension->is_platform_app() ? IDR_PLATFORM_APP_CSS : IDR_EXTENSION_CSS;
     std::string stylesheet = ResourceBundle::GetSharedInstance()
-                                 .GetRawDataResource(IDR_PLATFORM_APP_CSS)
+                                 .GetRawDataResource(resource_id)
                                  .as_string();
     ReplaceFirstSubstringAfterOffset(
         &stylesheet, 0, "$FONTFAMILY", system_font_family_);
     ReplaceFirstSubstringAfterOffset(
         &stylesheet, 0, "$FONTSIZE", system_font_size_);
+
+    // Blink doesn't let us define an additional user agent stylesheet, so
+    // we insert the default platform app or extension stylesheet into all
+    // documents that are loaded in each app or extension.
     frame->document().insertStyleSheet(WebString::fromUTF8(stylesheet));
   }
-
   content_watcher_->DidCreateDocumentElement(frame);
 }
 

extensions/renderer/resources/extension.css

+/*
+ * Copyright 2014 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.
+ *
+ * A style sheet for Chrome extensions.
+ */
+
+body {
+  font-family: $FONTFAMILY;
+  font-size: $FONTSIZE;
+}

extensions/renderer/resources/extensions_renderer_resources.grd

@@ -40,6 +40,9 @@
       <!-- Platform app support. -->
       <include name="IDR_PLATFORM_APP_CSS" file="platform_app.css" type="BINDATA" />
       <include name="IDR_PLATFORM_APP_JS" file="platform_app.js" type="BINDATA" />
+
+      <!-- Extension styles -->
+      <include name="IDR_EXTENSION_CSS" file="extension.css" type="BINDATA"/>
     </includes>
   </release>
 </grit>