[Android WebView] Implement the capture picture API.

ipc/ipc_channel_proxy.cc

Index: ipc/ipc_channel_proxy.cc
diff --git a/ipc/ipc_channel_proxy.cc b/ipc/ipc_channel_proxy.cc
index 0202e9e27ef665d13fe5dc30c01737fe5aaa1106..d5a965192f100f0fd6ad014e9f71814fc8b9cfa4 100644
--- a/ipc/ipc_channel_proxy.cc
+++ b/ipc/ipc_channel_proxy.cc
@@ -68,6 +68,18 @@ void ChannelProxy::Context::CreateChannel(const IPC::ChannelHandle& handle,
   channel_.reset(new Channel(handle, mode, this));
 }
 
+void ChannelProxy::Context::SendFailedSyncMessageReply(const Message& message) {
+  if (!message.is_sync())
+    return;
+
+  Message* reply = SyncMessage::GenerateReply(&message);
+  reply->set_reply_error();
+  ipc_task_runner()->PostTask(
+    FROM_HERE,
+    base::Bind(&ChannelProxy::Context::OnSendMessage,
+               this, base::Passed(scoped_ptr<Message>(reply))));
+}
+
 bool ChannelProxy::Context::TryFilters(const Message& message) {
 #ifdef IPC_MESSAGE_LOG_ENABLED
   Logging* logger = Logging::GetInstance();
@@ -243,14 +255,17 @@ void ChannelProxy::Context::OnDispatchMessage(const Message& message) {
                "line", IPC_MESSAGE_ID_LINE(message.type()));
 #endif
 
-  if (!listener_)
+  if (!listener_) {
+    SendFailedSyncMessageReply(message);
     return;
+  }
 
   OnDispatchConnected();
 
 #ifdef IPC_MESSAGE_LOG_ENABLED
   if (message.type() == IPC_LOGGING_ID) {
     logger->OnReceivedLoggingMessage(message);
+    SendFailedSyncMessageReply(message);
     return;
   }
 
@@ -258,7 +273,8 @@ void ChannelProxy::Context::OnDispatchMessage(const Message& message) {
     logger->OnPreDispatchMessage(message);
 #endif
 
-  listener_->OnMessageReceived(message);
+  if (!listener_->OnMessageReceived(message))
+    SendFailedSyncMessageReply(message);
 
 #ifdef IPC_MESSAGE_LOG_ENABLED
   if (logger->Enabled())