Plugin Power Saver: Add UI Overlay to throttled plugin using placeholder.

chrome/renderer/plugins/plugin_preroller.cc

+// Copyright 2015 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 "chrome/renderer/plugins/plugin_preroller.h"
+
+#include "base/base64.h"
+#include "chrome/grit/renderer_resources.h"
+#include "chrome/renderer/plugins/chrome_plugin_placeholder.h"
+#include "third_party/WebKit/public/platform/WebRect.h"
+#include "third_party/WebKit/public/web/WebElement.h"
+#include "third_party/WebKit/public/web/WebPlugin.h"
+#include "third_party/WebKit/public/web/WebPluginContainer.h"
+#include "ui/gfx/codec/png_codec.h"
+
+PluginPreroller::PluginPreroller(content::RenderFrame* render_frame,
+                                 blink::WebLocalFrame* frame,
+                                 const blink::WebPluginParams& params,
+                                 const content::WebPluginInfo& info,
+                                 const std::string& identifier,
+                                 const base::string16& name,
+                                 const base::string16& message,
+                                 blink::WebPlugin* plugin,
+                                 content::PluginInstanceThrottler* throttler)
+    : RenderFrameObserver(render_frame),
+      frame_(frame),
+      params_(params),
+      info_(info),
+      identifier_(identifier),
+      name_(name),
+      message_(message),
+      plugin_(plugin),
+      throttler_(throttler) {
+  DCHECK(plugin);
+  DCHECK(throttler);
+  throttler_->AddObserver(this);
+}
+
+PluginPreroller::~PluginPreroller() {
+  if (throttler_)
+    throttler_->RemoveObserver(this);
+}
+
+void PluginPreroller::OnKeyframeExtracted(const SkBitmap* bitmap) {
+  std::vector<unsigned char> png_data;
+  if (!gfx::PNGCodec::EncodeBGRASkBitmap(*bitmap, false, &png_data)) {
+    DLOG(ERROR) << "Provided keyframe could not be encoded as PNG.";
+    return;
+  }
+
+  base::StringPiece png_as_string(reinterpret_cast<char*>(&png_data[0]),
+                                  png_data.size());
+
+  std::string data_url_header = "data:image/png;base64,";
+  std::string data_url_body;
+  base::Base64Encode(png_as_string, &data_url_body);
+  keyframe_data_url_ = GURL(data_url_header + data_url_body);
+}
+
+void PluginPreroller::OnThrottleStateChange() {
+  if (!throttler_->IsThrottled())
+    return;
+
+  ChromePluginPlaceholder* placeholder =
+      ChromePluginPlaceholder::CreateBlockedPlugin(
+          render_frame(), frame_, params_, info_, identifier_, name_,
+          IDR_PLUGIN_POSTER_HTML, message_, keyframe_data_url_);
+  placeholder->SetPremadePlugin(plugin_, throttler_);
+  placeholder->set_power_saver_mode(
+      content::PluginPowerSaverMode::POWER_SAVER_MODE_PERIPHERAL_THROTTLED);
+  placeholder->set_allow_loading(true);
+
+  blink::WebPluginContainer* container = plugin_->container();
+  container->setPlugin(placeholder->plugin());
+
+  bool success = placeholder->plugin()->initialize(container);
+  DCHECK(success);
+
+  container->invalidate();
+  container->reportGeometry();
+
+  delete this;
+}
+
+void PluginPreroller::OnThrottlerDestroyed() {
+  throttler_ = nullptr;
+  delete this;
+}