[DevTools] Use InspectorFrontendHost.readyForTest for layout tests.

content/shell/browser/layout_test/layout_test_devtools_frontend.cc

Index: content/shell/browser/layout_test/layout_test_devtools_frontend.cc
diff --git a/content/shell/browser/layout_test/layout_test_devtools_frontend.cc b/content/shell/browser/layout_test/layout_test_devtools_frontend.cc
index 7da2af53ad64fb820513e6b131d081edd4c0546d..f30846ac661a286cb919ac2fbcbfc60da354a2a1 100644
--- a/content/shell/browser/layout_test/layout_test_devtools_frontend.cc
+++ b/content/shell/browser/layout_test/layout_test_devtools_frontend.cc
@@ -5,9 +5,13 @@
 #include "content/shell/browser/layout_test/layout_test_devtools_frontend.h"
 
 #include "base/command_line.h"
+#include "base/json/json_reader.h"
+#include "base/json/json_writer.h"
 #include "base/path_service.h"
 #include "base/strings/stringprintf.h"
+#include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
+#include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/shell/browser/layout_test/blink_test_controller.h"
 #include "content/shell/browser/shell.h"
@@ -67,13 +71,34 @@ void LayoutTestDevToolsFrontend::ReuseFrontend(const std::string& settings,
                                                const std::string frontend_url) {
   DisconnectFromTarget();
   preferences()->Clear();
+  ready_for_test_ = false;
+  pending_evaluations_.clear();
   frontend_shell()->LoadURL(GetDevToolsPathAsURL(settings, frontend_url));
 }
 
+void LayoutTestDevToolsFrontend::EvaluateInFrontend(
+    int call_id,
+    const std::string& script) {
+  if (!ready_for_test_) {
+    pending_evaluations_.push_back(std::make_pair(call_id, script));
+    return;
+  }
+
+  std::string encoded_script;
+  base::JSONWriter::Write(base::StringValue(script), &encoded_script);
+  std::string source =
+      base::StringPrintf("DevToolsAPI.evaluateForTestInFrontend(%d, %s);",
+                         call_id,
+                         encoded_script.c_str());
+  web_contents()->GetMainFrame()->ExecuteJavaScriptForTests(
+      base::UTF8ToUTF16(source));
+}
+
 LayoutTestDevToolsFrontend::LayoutTestDevToolsFrontend(
     Shell* frontend_shell,
     WebContents* inspected_contents)
-    : ShellDevToolsFrontend(frontend_shell, inspected_contents) {
+    : ShellDevToolsFrontend(frontend_shell, inspected_contents),
+      ready_for_test_(false) {
 }
 
 LayoutTestDevToolsFrontend::~LayoutTestDevToolsFrontend() {
@@ -84,6 +109,25 @@ void LayoutTestDevToolsFrontend::AgentHostClosed(
   // Do not close the front-end shell.
 }
 
+void LayoutTestDevToolsFrontend::HandleMessageFromDevToolsFrontend(
+    const std::string& message) {
+  std::string method;
+  base::DictionaryValue* dict = nullptr;
+  scoped_ptr<base::Value> parsed_message = base::JSONReader::Read(message);
+  if (parsed_message &&
+      parsed_message->GetAsDictionary(&dict) &&
+      dict->GetString("method", &method) &&
+      method == "readyForTest") {
+    ready_for_test_ = true;
+    for (const auto& pair : pending_evaluations_)
+      EvaluateInFrontend(pair.first, pair.second);
+    pending_evaluations_.clear();
+    return;
+  }
+
+  ShellDevToolsFrontend::HandleMessageFromDevToolsFrontend(message);
+}
+
 void LayoutTestDevToolsFrontend::RenderProcessGone(
     base::TerminationStatus status) {
   BlinkTestController::Get()->DevToolsProcessCrashed();