html_viewer: Add DevToolsAgentImpl.

components/html_viewer/html_document.cc

Index: components/html_viewer/html_document.cc
diff --git a/components/html_viewer/html_document.cc b/components/html_viewer/html_document.cc
index 4f678954e1683bd86c7e6c070b814e99e598b4de..d16f86baf63e50619a940d1d2aaf05244d710677 100644
--- a/components/html_viewer/html_document.cc
+++ b/components/html_viewer/html_document.cc
@@ -14,6 +14,7 @@
 #include "base/thread_task_runner_handle.h"
 #include "components/html_viewer/blink_input_events_type_converters.h"
 #include "components/html_viewer/blink_url_request_type_converters.h"
+#include "components/html_viewer/devtools_agent_impl.h"
 #include "components/html_viewer/media_factory.h"
 #include "components/html_viewer/setup.h"
 #include "components/html_viewer/web_layer_tree_view_impl.h"
@@ -164,8 +165,12 @@ void HTMLDocument::Load(URLResponsePtr response) {
   touch_handler_.reset(new TouchHandler(web_view_));
   web_layer_tree_view_impl_->set_widget(web_view_);
   ConfigureSettings(web_view_->settings());
-  web_view_->setMainFrame(
-      blink::WebLocalFrame::create(blink::WebTreeScopeType::Document, this));
+
+  blink::WebLocalFrame* main_frame =
+      blink::WebLocalFrame::create(blink::WebTreeScopeType::Document, this);
+  web_view_->setMainFrame(main_frame);
+
+  devtools_agent_.reset(new DevToolsAgentImpl(main_frame, shell_.get()));

[sky, 2015/06/02 23:28:32]

Why do we always create devtools agent? Shouldn't we only do it if needed?

[yzshen1, 2015/06/05 17:29:29]

This |devtools_agent_| registers itself with the DevTools service. It does
nothing else unless the DevTools service sets a client and runs commands on it.
It is probably not very costly. We always creates a similar object in Chrome too
in render_frame_impl.

If we want to create it on-demand:
Currently there isn't a clean way for the DevTools service to ask the
html_viewer to create |devtools_agent_|, because it has no way to query the
existing html_viewer instances.
That could be changed when we add such capability to the browser app. 

What do you think? Thanks!

[sky, 2015/06/05 19:13:30]

SG

 
   GURL url(response->url);
 
@@ -258,6 +263,9 @@ void HTMLDocument::frameDetached(blink::WebFrame* frame) {
   if (frame->parent())
     frame->parent()->removeChild(frame);
 
+  if (devtools_agent_ && frame == devtools_agent_->frame())
+    devtools_agent_.reset();
+
   // |frame| is invalid after here.
   frame->close();
 }