HeadlessWebContents Observers for devtools clients attaching/detatching

headless/lib/headless_devtools_client_browsertest.cc

Index: headless/lib/headless_devtools_client_browsertest.cc
diff --git a/headless/lib/headless_devtools_client_browsertest.cc b/headless/lib/headless_devtools_client_browsertest.cc
index dd4474b168b27377731a718bec1308d5c2627e47..79c5495da9ff7b9727d339df63f7d8744f9f36f7 100644
--- a/headless/lib/headless_devtools_client_browsertest.cc
+++ b/headless/lib/headless_devtools_client_browsertest.cc
@@ -1022,4 +1022,27 @@ class RawDevtoolsProtocolTest
 
 HEADLESS_ASYNC_DEVTOOLED_TEST_F(RawDevtoolsProtocolTest);
 
+class DevToolsAttachAndDetachNotifications
+    : public HeadlessAsyncDevTooledBrowserTest {
+ public:
+  void DevToolsClientAttached() override { dev_tools_client_attached_ = true; }
+
+  void RunDevTooledTest() override {
+    EXPECT_TRUE(dev_tools_client_attached_);
+    FinishAsynchronousTest();
+  }
+
+  void DevToolsClientDetached() override { dev_tools_client_detached_ = true; }
+
+  void TearDownOnMainThread() override {
+    EXPECT_TRUE(dev_tools_client_detached_);
+  }
+
+ private:
+  bool dev_tools_client_attached_ = false;
+  bool dev_tools_client_detached_ = false;
+};
+
+HEADLESS_ASYNC_DEVTOOLED_TEST_F(DevToolsAttachAndDetachNotifications);
+
 }  // namespace headless