Fix WebView compositor input handling

content/browser/android/in_process/synchronous_input_event_filter.cc

Index: content/browser/android/in_process/synchronous_input_event_filter.cc
diff --git a/content/browser/android/in_process/synchronous_input_event_filter.cc b/content/browser/android/in_process/synchronous_input_event_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ea5e6f162a6f22109b4a8fb1c7c38bf4e1a32efb
--- /dev/null
+++ b/content/browser/android/in_process/synchronous_input_event_filter.cc
@@ -0,0 +1,67 @@
+// Copyright (c) 2012 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.
+
+#include "content/browser/android/in_process/synchronous_input_event_filter.h"
+
+#include "base/callback.h"
+#include "base/logging.h"
+#include "content/public/browser/browser_thread.h"
+
+using WebKit::WebInputEvent;
+
+namespace content {
+
+SynchronousInputEventFilter::SynchronousInputEventFilter()
+    : handle_input_event_result_(NULL) {
+}
+
+SynchronousInputEventFilter::~SynchronousInputEventFilter() {
+}
+
+InputEventAckState SynchronousInputEventFilter::HandleInputEvent(
+    int routing_id,
+    const WebKit::WebInputEvent* input_event) {
+  // The handler will be empty both before renderer initialization and after
+  // renderer destruction. It's possible that this will be reached in such a
+  // state. While not good, it should also not be fatal.
+  if (handler_.is_null())
+    return INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS;
+
+  InputEventAckState result = INPUT_EVENT_ACK_STATE_UNKNOWN;
+  handle_input_event_result_ = &result;
+
+  // It is expected that handler_ initiates a synchronous callback to
+  // Did/DidNotHandleInputEvent.
+  handler_.Run(routing_id, input_event);
+  DCHECK(result != INPUT_EVENT_ACK_STATE_UNKNOWN);
+
+  handle_input_event_result_ = NULL;
+  return result;
+}
+
+void SynchronousInputEventFilter::SetHandler(const Handler& handler) {
+  BrowserThread::GetMessageLoopProxyForThread(BrowserThread::UI)->
+    PostTask(FROM_HERE,
+             base::Bind(&SynchronousInputEventFilter::SetHandlerOnUIThread,
+                        base::Unretained(this),
+                        handler));
+}
+
+void SynchronousInputEventFilter::DidHandleInputEvent() {
+  DCHECK(handle_input_event_result_);
+  *handle_input_event_result_ = INPUT_EVENT_ACK_STATE_CONSUMED;
+}
+
+void SynchronousInputEventFilter::DidNotHandleInputEvent(bool send_to_widget) {
+  DCHECK(handle_input_event_result_);
+  *handle_input_event_result_ =
+      send_to_widget ? INPUT_EVENT_ACK_STATE_NOT_CONSUMED
+                     : INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS;
+}
+
+void SynchronousInputEventFilter::SetHandlerOnUIThread(const Handler& handler) {
+  handler_ = handler;
+}
+
+}  // namespace content