[chromecast] Enable Mojo javascript bindings for cast_shell

chromecast/renderer/cast_content_renderer_client.cc

 // 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.
 
 #include "chromecast/renderer/cast_content_renderer_client.h"
 
 #include <stdint.h>
+#include <string>
 
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "chromecast/base/chromecast_switches.h"
 #include "chromecast/common/media/cast_media_client.h"
 #include "chromecast/crash/cast_crash_keys.h"
+#include "chromecast/renderer/cast_gin_runner.h"
 #include "chromecast/renderer/cast_media_load_deferrer.h"
 #include "chromecast/renderer/cast_render_thread_observer.h"
 #include "chromecast/renderer/key_systems_cast.h"
 #include "chromecast/renderer/media/chromecast_media_renderer_factory.h"
 #include "chromecast/renderer/media/media_caps_observer_impl.h"
 #include "components/network_hints/renderer/prescient_networking_dispatcher.h"
+#include "content/grit/content_resources.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/renderer/render_frame.h"
 #include "content/public/renderer/render_thread.h"
 #include "content/public/renderer/render_view.h"
+#include "gin/modules/module_registry.h"
+#include "gin/per_context_data.h"
+#include "gin/public/context_holder.h"
 #include "media/base/media.h"
 #include "services/shell/public/cpp/interface_provider.h"
 #include "third_party/WebKit/public/platform/WebColor.h"
 #include "third_party/WebKit/public/web/WebFrameWidget.h"
+#include "third_party/WebKit/public/web/WebKit.h"
+#include "third_party/WebKit/public/web/WebLocalFrame.h"
 #include "third_party/WebKit/public/web/WebSettings.h"
 #include "third_party/WebKit/public/web/WebView.h"
+#include "ui/base/resource/resource_bundle.h"
 
 #if defined(OS_ANDROID)
 #include "media/base/android/media_codec_util.h"
 #endif  // OS_ANDROID
 
+namespace {
+
+const char kCastContextStateKey[] = "CastContextState";
+
+}  // namespace
+
 namespace chromecast {
 namespace shell {
 
 namespace {
 
 // Default background color to set for WebViews. WebColor is in ARGB format
 // though the comment of WebColor says it is in RGBA.
 const blink::WebColor kColorBlack = 0xFF000000;
 
 }  // namespace
@@ skipping 94 matching lines @@
     const base::Closure& closure) {
   if (!render_frame->IsHidden() || allow_hidden_media_playback_) {
     closure.Run();
     return;
   }
 
   // Lifetime is tied to |render_frame| via content::RenderFrameObserver.
   new CastMediaLoadDeferrer(render_frame, closure);
 }
 
+void CastContentRendererClient::ExecuteJavaScript(
+    content::RenderFrame* render_frame, int resource_id) {

[derekjchow1, 2016/09/15 00:48:02]

DCHECK(render_frame)

[jam, 2016/09/15 16:30:12]

note this isn't really needed, since if render_frame is null then two lines down
will crash which is just as useful of a signal

+  const std::string& js_string = ui::ResourceBundle::GetSharedInstance()
+                                     .GetRawDataResource(resource_id)
+                                     .as_string();
+  render_frame->ExecuteJavaScript(base::UTF8ToUTF16(js_string));
+}
+
+void CastContentRendererClient::RunScriptsAtDocumentStart(
+    content::RenderFrame* render_frame) {
+  // This method enables Mojo bindings in JavaScript for Chromecast.
+
+  v8::HandleScope handle_scope(blink::mainThreadIsolate());
+  blink::WebLocalFrame* frame = render_frame->GetWebFrame();

[derekjchow1, 2016/09/15 00:48:02]

You can probably move lines 179 & 181-183 into the constructor of CastGinRunner.
We only need |frame|.

+  v8::Local<v8::Context> context = frame->mainWorldScriptContext();
+  gin::PerContextData* context_data = gin::PerContextData::From(context);
+  gin::ContextHolder* context_holder = context_data->context_holder();
+  CastGinRunner* runner = new CastGinRunner(frame, context_holder);
+  context_data->SetUserData(kCastContextStateKey, runner);

[derekjchow1, 2016/09/15 00:48:02]

Will runner get leaked if you do not explicitly remove it? I think it does. You
might want to do something like MojoBindingsController by making CastGinRunner a
RenderFrameObserver{Tracker}, and cleaning up when the following functions are
called:

  void WillReleaseScriptContext(v8::Local<v8::Context> context,
                                int world_id) override;
  void DidClearWindowObject() override;

https://cs.chromium.org/chromium/src/content/renderer/mojo_bindings_controller.h

[jarhar, 2016/09/16 03:29:41]

Done.

+  gin::Runner::Scope scoper(runner);
+
+  // Initialize AMD API for Mojo.
+  render_frame->EnsureMojoBuiltinsAreAvailable(context_holder->isolate(),
+                                               context);
+  gin::ModuleRegistry::InstallGlobals(context_holder->isolate(),
+                                      context->Global());
+
+  // Inject JavaScript files in the correct dependency order.
+  static const int mojoResourceIds[] = {

[alokp, 2016/09/16 04:27:22]

mojoResourceIds -> mojo_resource_ids

[jarhar, 2016/09/16 20:54:22]

Done.

+      IDR_MOJO_UNICODE_JS,
+      IDR_MOJO_BUFFER_JS,
+      IDR_MOJO_CODEC_JS,
+      IDR_MOJO_CONNECTOR_JS,
+      IDR_MOJO_VALIDATOR_JS,
+      IDR_MOJO_ROUTER_JS,
+      IDR_MOJO_BINDINGS_JS,
+      IDR_MOJO_CONNECTION_JS,
+  };
+  for (size_t i = 0; i < arraysize(mojoResourceIds); i++) {
+    ExecuteJavaScript(render_frame, mojoResourceIds[i]);
+  }
+}
+
 }  // namespace shell
 }  // namespace chromecast