Revert "Dispatch interfacerequest event in a new microtask"

This reverts commit fe5c2f3d.

Reason for revert: This appears to be causing flake in the WebUSB layout tests.

Original change's description:
> Dispatch interfacerequest event in a new microtask
> 
> This change modifies the MojoInterfaceInterceptor so that the
> 'interfacerequest' event, fired when a request for the intercepted
> interface is made, is dispatched in a new microtask instead of
> synchronously.
> 
> This has the benefit of not reentering JavaScript to execute event
> handlers synchronously which is both different from the usual case for
> binding interfaces that are provided by other processes and avoids the
> possibilty of attempting to dispatch this event to JavaScript from a
> scope where script is forbidden.
> 
> Change-Id: I08b8c25a04da047381a3786af08b62979ca7b837
> Reviewed-on: https://chromium-review.googlesource.com/594716
> Reviewed-by: Daniel Cheng <dcheng@chromium.org>
> Reviewed-by: Yuzhu Shen <yzshen@chromium.org>
> Commit-Queue: Reilly Grant <reillyg@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#491552}

TBR=dcheng@chromium.org,yzshen@chromium.org,reillyg@chromium.org

Change-Id: Ibc179e1313fceba9a6e8da37e5220ccb6aa7c204
Bug: 751955
Reviewed-on: https://chromium-review.googlesource.com/601007
Commit-Queue: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491864}

third_party/WebKit/LayoutTests/TestExpectations

@@ -3097,6 +3097,3 @@ crbug.com/749738 [ Win7 Debug ] http/tests/devtools/console/console-format-es6-2
 crbug.com/749738 [ Win7 Debug ] virtual/mojo-loading/http/tests/devtools/console/console-format-es6-2.js [ Timeout ]
 crbug.com/749965 [ Win7 Debug ] media/controls/controls-video-keynav.html [ Failure ]
 crbug.com/750310 [ Win7 Debug ] virtual/off-main-thread-fetch/http/tests/inspector/network/network-blocked-reason.html [ Timeout ]
-
-# Sheriff failures 2017-08-03
-crbug.com/751955 external/wpt/webusb/idlharness.https.html [ Timeout Pass ]

third_party/WebKit/LayoutTests/mojo/bind-interface.html

@@ -77,41 +77,25 @@ promise_test(() => {
   return Promise.reject();
 }, "interface interceptors are mutually exclusive");
 
-test(async t => {
+test(() => {
   const kTestInterfaceName = "foo::mojom::Bar";
+  let interceptedHandle = null;
 
-  // First check that the interceptor can be started and intercepts requests.
   let interceptor = new MojoInterfaceInterceptor(kTestInterfaceName);
-  let promise = new Promise(resolve => {
-    interceptor.oninterfacerequest = e => {
-      resolve(e.handle);
-    };
-  });
+  interceptor.oninterfacerequest = e => { interceptedHandle = e.handle; };
   interceptor.start();
 
-  let pipe = Mojo.createMessagePipe();
-  Mojo.bindInterface(kTestInterfaceName, pipe.handle0);
-  let interceptedHandle = await promise;
+  let {handle0, handle1} = Mojo.createMessagePipe();
+  Mojo.bindInterface(kTestInterfaceName, handle0);
+  interceptor.stop();
+
   assert_true(interceptedHandle instanceof MojoHandle);
   interceptedHandle.close();
-  pipe.handle1.close();
+  interceptedHandle = null;
 
-  // Stop the interceptor and make another request.
-  interceptor.stop();
-
-  pipe = Mojo.createMessagePipe();
-  interceptor.oninterfacerequest = t.step_func(() => {
-    assert_unreached("unexpected 'interfacerequest' event after stop");
-  });
-  promise = new Promise(resolve => {
-    let watcher = pipe.handle1.watch({peerClosed: true}, () => {
-      watcher.cancel();  // Necessary to avoid a DCHECK when handle1 is closed.
-      resolve();
-    });
-  });
-  Mojo.bindInterface(kTestInterfaceName, pipe.handle0);
-  await promise;
-  pipe.handle1.close();
+  Mojo.bindInterface(kTestInterfaceName, handle1);
+  assert_equals(interceptedHandle, null);
+  handle1.close();
 
   interceptor = new MojoInterfaceInterceptor(kTestInterfaceName);
   interceptor.oninterfacerequest = e => {};

third_party/WebKit/Source/core/mojo/test/MojoInterfaceInterceptor.cpp

@@ -7,7 +7,6 @@
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExecutionContext.h"
-#include "core/dom/TaskRunnerHelper.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/LocalFrameClient.h"
@@ -15,7 +14,6 @@
 #include "core/mojo/test/MojoInterfaceRequestEvent.h"
 #include "core/workers/WorkerGlobalScope.h"
 #include "core/workers/WorkerThread.h"
-#include "platform/WebTaskRunner.h"
 #include "platform/bindings/ScriptState.h"
 #include "platform/wtf/text/StringUTF8Adaptor.h"
 #include "services/service_manager/public/cpp/interface_provider.h"
@@ -120,20 +118,6 @@ MojoInterfaceInterceptor::GetInterfaceProvider() const {
 
 void MojoInterfaceInterceptor::OnInterfaceRequest(
     mojo::ScopedMessagePipeHandle handle) {
-  // Execution of JavaScript may be forbidden in this context as this method is
-  // called synchronously by the InterfaceProvider. Dispatching of the
-  // 'interfacerequest' event is therefore scheduled to take place in the next
-  // microtask. This also more closely mirrors the behavior when an interface
-  // request is being satisfied by another process.
-  TaskRunnerHelper::Get(TaskType::kMicrotask, GetExecutionContext())
-      ->PostTask(
-          BLINK_FROM_HERE,
-          WTF::Bind(&MojoInterfaceInterceptor::DispatchInterfaceRequestEvent,
-                    WrapPersistent(this), WTF::Passed(std::move(handle))));
-}
-
-void MojoInterfaceInterceptor::DispatchInterfaceRequestEvent(
-    mojo::ScopedMessagePipeHandle handle) {
   DispatchEvent(MojoInterfaceRequestEvent::Create(
       MojoHandle::Create(mojo::ScopedHandle::From(std::move(handle)))));
 }

third_party/WebKit/Source/core/mojo/test/MojoInterfaceInterceptor.h

@@ -65,7 +65,6 @@ class MojoInterfaceInterceptor final
 
   service_manager::InterfaceProvider* GetInterfaceProvider() const;
   void OnInterfaceRequest(mojo::ScopedMessagePipeHandle);
-  void DispatchInterfaceRequestEvent(mojo::ScopedMessagePipeHandle);
 
   const String interface_name_;
   bool started_ = false;