Plugin Placeholders: Refactor for platforms that don't support plugins

components/plugins/renderer/plugin_placeholder.cc

 // Copyright 2013 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.
 
 #include "components/plugins/renderer/plugin_placeholder.h"
 
+#include "base/strings/string_util.h"
 #include "content/public/renderer/render_frame.h"
+#include "content/public/renderer/render_thread.h"
+#include "gin/object_template_builder.h"
+#include "third_party/WebKit/public/web/WebElement.h"
+#include "third_party/WebKit/public/web/WebPluginContainer.h"
+#include "third_party/re2/re2/re2.h"
 
 namespace plugins {
 
+// The placeholder is loaded in normal web renderer processes, so it should not
+// have a chrome:// scheme that might let it be confused with a WebUI page.
+const char kPluginPlaceholderDataURL[] = "data:text/html,pluginplaceholderdata";
+
 gin::WrapperInfo PluginPlaceholder::kWrapperInfo = {gin::kEmbedderNativeGin};
 
 PluginPlaceholder::PluginPlaceholder(content::RenderFrame* render_frame,
                                      blink::WebLocalFrame* frame,
                                      const blink::WebPluginParams& params,
-                                     const std::string& html_data,
-                                     GURL placeholderDataUrl)
+                                     const std::string& html_data)
     : content::RenderFrameObserver(render_frame),
       frame_(frame),
       plugin_params_(params),
       plugin_(WebViewPlugin::Create(this,
                                     render_frame->GetWebkitPreferences(),
                                     html_data,
-                                    placeholderDataUrl)) {
-  DCHECK(placeholderDataUrl.is_valid())
-      << "Blink requires the placeholder to have a valid URL.";
+                                    GURL(kPluginPlaceholderDataURL))),
+      hidden_(false) {
 }
 
 PluginPlaceholder::~PluginPlaceholder() {}
 
 const blink::WebPluginParams& PluginPlaceholder::GetPluginParams() const {
   return plugin_params_;
 }
 
+void PluginPlaceholder::BindWebFrame(blink::WebFrame* frame) {
+  v8::Isolate* isolate = blink::mainThreadIsolate();
+  v8::HandleScope handle_scope(isolate);
+  v8::Local<v8::Context> context = frame->mainWorldScriptContext();
+  DCHECK(!context.IsEmpty());
+
+  v8::Context::Scope context_scope(context);
+  v8::Local<v8::Object> global = context->Global();
+  global->Set(gin::StringToV8(isolate, "plugin"),
+              gin::CreateHandle(isolate, this).ToV8());
+}
+
 void PluginPlaceholder::ShowContextMenu(const blink::WebMouseEvent& event) {
   // Does nothing by default. Will be overridden if a specific browser wants
   // a context menu.
   return;
 }
 
 void PluginPlaceholder::PluginDestroyed() {
   plugin_ = NULL;
 }
 
 v8::Local<v8::Object> PluginPlaceholder::GetV8ScriptableObject(
     v8::Isolate* isolate) const {
   return v8::Local<v8::Object>();
 }
 
+gin::ObjectTemplateBuilder PluginPlaceholder::GetObjectTemplateBuilder(
+    v8::Isolate* isolate) {
+  return gin::Wrappable<PluginPlaceholder>::GetObjectTemplateBuilder(isolate)
+      .SetMethod("hide", &PluginPlaceholder::HideCallback);
+}
+
+void PluginPlaceholder::HidePlugin() {
+  hidden_ = true;
+  if (!plugin())
+    return;
+  blink::WebPluginContainer* container = plugin()->container();
+  blink::WebElement element = container->element();
+  element.setAttribute("style", "display: none;");
+  // If we have a width and height, search for a parent (often <div>) with the
+  // same dimensions. If we find such a parent, hide that as well.
+  // This makes much more uncovered page content usable (including clickable)
+  // as opposed to merely visible.
+  // TODO(cevans) -- it's a foul heuristic but we're going to tolerate it for
+  // now for these reasons:
+  // 1) Makes the user experience better.
+  // 2) Foulness is encapsulated within this single function.
+  // 3) Confidence in no fasle positives.
+  // 4) Seems to have a good / low false negative rate at this time.
+  if (element.hasAttribute("width") && element.hasAttribute("height")) {
+    std::string width_str("width:[\\s]*");
+    width_str += element.getAttribute("width").utf8().data();
+    if (EndsWith(width_str, "px", false)) {
+      width_str = width_str.substr(0, width_str.length() - 2);
+    }
+    base::TrimWhitespace(width_str, base::TRIM_TRAILING, &width_str);
+    width_str += "[\\s]*px";
+    std::string height_str("height:[\\s]*");
+    height_str += element.getAttribute("height").utf8().data();
+    if (EndsWith(height_str, "px", false)) {
+      height_str = height_str.substr(0, height_str.length() - 2);
+    }
+    base::TrimWhitespace(height_str, base::TRIM_TRAILING, &height_str);
+    height_str += "[\\s]*px";
+    blink::WebNode parent = element;
+    while (!parent.parentNode().isNull()) {
+      parent = parent.parentNode();
+      if (!parent.isElementNode())
+        continue;
+      element = parent.toConst<blink::WebElement>();
+      if (element.hasAttribute("style")) {
+        std::string style_str = element.getAttribute("style").utf8();
+        if (RE2::PartialMatch(style_str, width_str) &&
+            RE2::PartialMatch(style_str, height_str))
+          element.setAttribute("style", "display: none;");
+      }
+    }
+  }
+}
+
 void PluginPlaceholder::OnDestruct() {
   frame_ = NULL;
 }
 
+void PluginPlaceholder::HideCallback() {
+  content::RenderThread::Get()->RecordAction(
+      base::UserMetricsAction("Plugin_Hide_Click"));
+  HidePlugin();
+}
+
 blink::WebLocalFrame* PluginPlaceholder::GetFrame() { return frame_; }
 
 }  // namespace plugins