DevTools: response writers need to post to the UI while sending into streams.

content/shell/browser/shell_devtools_frontend.cc

Index: content/shell/browser/shell_devtools_frontend.cc
diff --git a/content/shell/browser/shell_devtools_frontend.cc b/content/shell/browser/shell_devtools_frontend.cc
index 28c63f1d458c22d9a79f25603f6534ebd3cf6ad4..f2d0d0ca6576b9ab095f3d727b38e98d263837c0 100644
--- a/content/shell/browser/shell_devtools_frontend.cc
+++ b/content/shell/browser/shell_devtools_frontend.cc
@@ -7,9 +7,11 @@
 #include "base/command_line.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
+#include "base/lazy_instance.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/devtools_http_handler.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_view_host.h"
@@ -32,12 +34,15 @@ namespace content {
 
 namespace {
 
+using StreamOwners = std::map<int, Shell*>;
+base::LazyInstance<StreamOwners>::Leaky g_stream_owners =
+    LAZY_INSTANCE_INITIALIZER;
 
 // ResponseWriter -------------------------------------------------------------
 
 class ResponseWriter : public net::URLFetcherResponseWriter {
  public:
-  ResponseWriter(Shell* shell, int stream_id);
+  explicit ResponseWriter(int stream_id);
   ~ResponseWriter() override;
 
   // URLFetcherResponseWriter overrides:
@@ -48,16 +53,13 @@ class ResponseWriter : public net::URLFetcherResponseWriter {
   int Finish(const net::CompletionCallback& callback) override;
 
  private:
-  Shell* shell_;
   int stream_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ResponseWriter);
 };
 
-ResponseWriter::ResponseWriter(Shell* shell,
-                               int stream_id)
-    : shell_(shell),
-      stream_id_(stream_id) {
+ResponseWriter::ResponseWriter(int stream_id)
+    : stream_id_(stream_id) {
 }
 
 ResponseWriter::~ResponseWriter() {
@@ -67,26 +69,35 @@ int ResponseWriter::Initialize(const net::CompletionCallback& callback) {
   return net::OK;
 }
 
+static void RespondOnUI(int stream_id, const std::string& code) {
+  auto it = g_stream_owners.Get().find(stream_id);
+  if (it != g_stream_owners.Get().end()) {
+    it->second->web_contents()->GetMainFrame()->ExecuteJavaScript(
+      base::UTF8ToUTF16(code));
+  }
+}
+
 int ResponseWriter::Write(net::IOBuffer* buffer,
                           int num_bytes,
                           const net::CompletionCallback& callback) {
   base::StringValue chunk(std::string(buffer->data(), num_bytes));
   std::string encoded;
   base::JSONWriter::Write(&chunk, &encoded);
-
   std::string code = base::StringPrintf(
       "DevToolsAPI.streamWrite(%d, %s)", stream_id_, encoded.c_str());
-  shell_->web_contents()->GetMainFrame()->ExecuteJavaScript(
-      base::UTF8ToUTF16(code));
 
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&RespondOnUI, stream_id_, code));
   return num_bytes;
 }
 
 int ResponseWriter::Finish(const net::CompletionCallback& callback) {
   std::string code = base::StringPrintf(
       "DevToolsAPI.streamFinish(%d)", stream_id_);
-  shell_->web_contents()->GetMainFrame()->ExecuteJavaScript(
-      base::UTF8ToUTF16(code));
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&RespondOnUI, stream_id_, code));
   return net::OK;
 }
 
@@ -151,6 +162,14 @@ ShellDevToolsFrontend::ShellDevToolsFrontend(Shell* frontend_shell,
 ShellDevToolsFrontend::~ShellDevToolsFrontend() {
   for (const auto& pair : pending_requests_)
     delete pair.first;
+
+  for (auto it = g_stream_owners.Get().begin();
+       it != g_stream_owners.Get().end(); ) {
+    if (it->second == frontend_shell())
+      g_stream_owners.Get().erase(it);
+    else
+      ++it;
+  }
 }
 
 void ShellDevToolsFrontend::RenderViewCreated(
@@ -217,14 +236,16 @@ void ShellDevToolsFrontend::HandleMessageFromDevToolsFrontend(
       return;
     }
 
+    g_stream_owners.Get()[stream_id] = frontend_shell();
+
     net::URLFetcher* fetcher =
         net::URLFetcher::Create(gurl, net::URLFetcher::GET, this);
-    pending_requests_[fetcher] = id;
+    pending_requests_[fetcher] = std::make_pair(id, stream_id);
     fetcher->SetRequestContext(web_contents()->GetBrowserContext()->
         GetRequestContext());
     fetcher->SetExtraRequestHeaders(headers);
     fetcher->SaveResponseWithWriter(scoped_ptr<net::URLFetcherResponseWriter>(
-        new ResponseWriter(frontend_shell(), stream_id)));
+        new ResponseWriter(stream_id)));
     fetcher->Start();
     return;
   } else {
@@ -288,13 +309,16 @@ void ShellDevToolsFrontend::OnURLFetchComplete(const net::URLFetcher* source) {
   std::string json;
   base::JSONWriter::Write(&response, &json);
 
+  int request_id = it->second.first;
+  int stream_id = it->second.second;
   std::string message = base::StringPrintf(
       "DevToolsAPI.embedderMessageAck(%d, %s)",
-      it->second,
+      request_id,
       json.c_str());
   web_contents()->GetMainFrame()->
       ExecuteJavaScript(base::UTF8ToUTF16(message));
 
+  g_stream_owners.Get().erase(stream_id);
   pending_requests_.erase(it);
   delete source;
 }