Fix WebView compositor input handling

content/renderer/android/synchronous_input_event_filter.h

Index: content/renderer/android/synchronous_input_event_filter.h
diff --git a/content/renderer/android/synchronous_input_event_filter.h b/content/renderer/android/synchronous_input_event_filter.h
new file mode 100644
index 0000000000000000000000000000000000000000..6a723a802a4a8b0228524d3c702a4c6411568bad
--- /dev/null
+++ b/content/renderer/android/synchronous_input_event_filter.h
@@ -0,0 +1,54 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_RENDERER_ANDROID_SYNCHRONOUS_INPUT_EVENT_FILTER_H_
+#define CONTENT_RENDERER_ANDROID_SYNCHRONOUS_INPUT_EVENT_FILTER_H_
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "content/port/common/input_event_ack_state.h"
+#include "content/renderer/gpu/input_handler_manager_client.h"
+
+namespace WebKit {
+class WebInputEvent;
+}
+
+namespace content {
+
+// This class perform synchronous, in-process InputEvent handling.
+//
+// The user of this class provides an instance of InputEventFilter::Handler,
+// which will be passed WebInputEvents on the compositing thread. If the event
+// goes unhandled, that is reflected in the InputEventAckState; no forwarding
+// is performed.
+//
+// It is up to the user to ensure thread-safety.

[joth, 2013/05/31 18:05:08]

user means caller, or sub-classer?

[jdduke (slow), 2013/05/31 20:48:24]

Caller. I'll make that clear.

+class SynchronousInputEventFilter : public InputHandlerManagerClient {

[joth, 2013/05/31 18:05:08]

feels like this whole class could now live in
content/browser/android/in_process? It's basically an implementation detail of
SyncCompositorImpl. The important interface is input_handler_manager_client.h --
we'd need to open up DEPS a bit to let in_process/... see all of content/render,
but that seems fine to me.

WDYT?

[jdduke (slow), 2013/05/31 20:48:24]

Hmm, I put it here because it has a content/renderer dependency
(InputHandlerManagerClient), but it looks like we don't have that restriction
for content/browser/android/in_process members, so I'd be happy for it to live
there. Done.

+ public:
+  SynchronousInputEventFilter();
+  virtual ~SynchronousInputEventFilter();
+
+  InputEventAckState HandleInputEvent(int routing_id,
+                                      const WebKit::WebInputEvent* input_event);
+
+  // InputHandlerManagerClient implementation.
+  virtual void DidBind(const Handler& handler);
+  virtual void DidAddInputHandler(int routing_id) OVERRIDE {}
+  virtual void DidRemoveInputHandler(int routing_id) OVERRIDE {}
+  virtual void DidHandleInputEvent() OVERRIDE;
+  virtual void DidNotHandleInputEvent(bool send_to_widget) OVERRIDE;
+
+ private:
+  Handler handler_;
+
+  // A temporary result reflecting the intermediate callback sequence of
+  // Did/DidNotHandleInputEvent, initiated by a call to HandleInputEvent. This
+  // does not affect external state.
+  InputEventAckState event_result_;

[joth, 2013/05/31 18:05:08]

To make this super-clear, you _could_ turn this into a InputEventAckState* and
have it only be non-NULL during the  HandleInputEvent() call (pointing to a
stack var).
I'm fine either way.

[jdduke (slow), 2013/05/31 20:48:24]

Done.

+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_ANDROID_SYNCHRONOUS_INPUT_EVENT_FILTER_H_