Bubble scroll events from WebView guest to embedder.

content/renderer/browser_plugin/browser_plugin_manager.cc

 // 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/renderer/browser_plugin/browser_plugin_manager.h"
+
 #include "base/memory/scoped_ptr.h"
+#include "base/threading/thread.h"
+#include "cc/base/completion_event.h"
 #include "content/common/browser_plugin/browser_plugin_constants.h"
 #include "content/common/browser_plugin/browser_plugin_messages.h"
 #include "content/common/frame_messages.h"
 #include "content/public/renderer/browser_plugin_delegate.h"
 #include "content/renderer/browser_plugin/browser_plugin.h"
 #include "content/renderer/render_thread_impl.h"
 #include "ipc/ipc_message_macros.h"
+#include "ipc/ipc_sync_channel.h"
+#include "ipc/message_filter.h"
 
 namespace content {
 
+class GuestScrollCompletionFilter : public IPC::MessageFilter {
+ public:
+  explicit GuestScrollCompletionFilter(
+      scoped_refptr<base::SingleThreadTaskRunner> io_task_runner)
+      : io_task_runner_(io_task_runner),
+        guest_handled_scroll_event_(true),
+        scroll_completion_event_(nullptr) {}
+
+  // IPC::MessageFilter implementation.
+  bool OnMessageReceived(const IPC::Message& message) override {
+    DCHECK(io_task_runner_->BelongsToCurrentThread());
+    // If we see the as-yet-to-be determined ack from the browser,
+    // set |guest_handled_scroll_event_| and call
+    // scroll_completion_event_->Signal().
+    bool handled = true;
+    IPC_BEGIN_MESSAGE_MAP(GuestScrollCompletionFilter, message)
+      IPC_MESSAGE_HANDLER(BrowserPluginMsg_SignalScrollCompletionEvent,
+                          OnSignalScrollCompletionEvent)
+      IPC_MESSAGE_UNHANDLED(handled = false)
+    IPC_END_MESSAGE_MAP()
+    return handled;
+  }
+
+  void set_scroll_completion_event(
+      cc::CompletionEvent* scroll_completion_event) {
+    scroll_completion_event_ = scroll_completion_event;
+  }
+  bool guest_handled_scroll_event() const {
+    return guest_handled_scroll_event_;
+  }
+
+ private:
+  ~GuestScrollCompletionFilter() override {}
+
+  scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
+  bool guest_handled_scroll_event_;
+  cc::CompletionEvent* scroll_completion_event_;
+
+  void OnSignalScrollCompletionEvent(bool handled) {
+    DCHECK(io_task_runner_->BelongsToCurrentThread());
+    guest_handled_scroll_event_ = handled;
+    scroll_completion_event_->Signal();
+    scroll_completion_event_ = nullptr;
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(GuestScrollCompletionFilter);
+};
+
 // static
 BrowserPluginManager* BrowserPluginManager::Get() {
   if (!RenderThreadImpl::current())
     return nullptr;
   return RenderThreadImpl::current()->browser_plugin_manager();
 }
 
 BrowserPluginManager::BrowserPluginManager() {
 }
 
 BrowserPluginManager::~BrowserPluginManager() {
 }
 
+void BrowserPluginManager::Init(
+    scoped_refptr<base::SingleThreadTaskRunner> io_task_runner,
+    IPC::SyncChannel* channel) {
+  scroll_completion_filter_ = new GuestScrollCompletionFilter(io_task_runner);
+  channel->AddFilter(scroll_completion_filter_.get());
+}
+
 void BrowserPluginManager::AddBrowserPlugin(
     int browser_plugin_instance_id,
     BrowserPlugin* browser_plugin) {
   instances_.AddWithID(browser_plugin, browser_plugin_instance_id);
 }
 
 void BrowserPluginManager::RemoveBrowserPlugin(int browser_plugin_instance_id) {
   instances_.Remove(browser_plugin_instance_id);
 }
 
@@ skipping 66 matching lines @@
     return true;
   }
 
   return false;
 }
 
 bool BrowserPluginManager::Send(IPC::Message* msg) {
   return RenderThreadImpl::current()->Send(msg);
 }
 
+bool BrowserPluginManager::GetScrollHandledStatus() {
+  cc::CompletionEvent scroll_completion_event;
+
+  scroll_completion_filter_->set_scroll_completion_event(
+      &scroll_completion_event);
+  scroll_completion_event.Wait();
+  return scroll_completion_filter_->guest_handled_scroll_event();
+}
+
 void BrowserPluginManager::OnCompositorFrameSwappedPluginUnavailable(
     const IPC::Message& message) {
   BrowserPluginMsg_CompositorFrameSwapped::Param param;
   if (!BrowserPluginMsg_CompositorFrameSwapped::Read(&message, &param))
     return;
 
   FrameHostMsg_CompositorFrameSwappedACK_Params params;
   params.producing_host_id = base::get<1>(param).producing_host_id;
   params.producing_route_id = base::get<1>(param).producing_route_id;
   params.output_surface_id = base::get<1>(param).output_surface_id;
   Send(new BrowserPluginHostMsg_CompositorFrameSwappedACK(
       base::get<0>(param), params));
 }
 
 }  // namespace content