[DeviceService] Mojofy left screen orientation IPC messages.

content/browser/screen_orientation/screen_orientation_message_filter_android.cc

Index: content/browser/screen_orientation/screen_orientation_message_filter_android.cc
diff --git a/content/browser/screen_orientation/screen_orientation_message_filter_android.cc b/content/browser/screen_orientation/screen_orientation_message_filter_android.cc
index cd7bd186a22fadbcaba9f140079363aba1250d1d..fc3dd7a4da358f7917fc5f21cc523fbd6284157c 100644
--- a/content/browser/screen_orientation/screen_orientation_message_filter_android.cc
+++ b/content/browser/screen_orientation/screen_orientation_message_filter_android.cc
@@ -6,40 +6,38 @@
 
 #include "content/browser/screen_orientation/screen_orientation_delegate_android.h"
 #include "content/common/screen_orientation_messages.h"
+#include "content/public/browser/browser_thread.h"
 
 namespace content {
 
 ScreenOrientationMessageFilterAndroid::ScreenOrientationMessageFilterAndroid()
-    : BrowserMessageFilter(ScreenOrientationMsgStart)
-    , listeners_count_(0) {
-}
+    : BrowserMessageFilter(ScreenOrientationMsgStart),
+      BrowserAssociatedInterface<device::mojom::ScreenOrientationAccurate>(
+          this,
+          this),
+      listeners_count_(0) {}
 
 ScreenOrientationMessageFilterAndroid::~ScreenOrientationMessageFilterAndroid()
 {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);

[blundell, 2016/12/20 13:39:18]

Let's use a base::ThreadChecker instead since we'll want to move this class out
of //content at some point. In the constructor you can check
base::MessageLoopForIO::IsCurrent().

[leonhsl(Using Gerrit), 2016/12/21 02:48:36]

Done.
Because ScreenOrientationMessageFilterAndroid is expected to be created on
render main thread while running all other member functions on IO thread, I
think base::ThreadChecker does not fit such case.
So I changed to use DCHECK(base::MessageLoopForIO::IsCurrent()) instead of
DCHECK_CURRENTLY_ON(content::BrowserThread::IO) throughout this file, to
explicitly check IO thread execution and can also avoid dependency on
content::BrowserThread.

   if (listeners_count_ > 0)
     ScreenOrientationDelegateAndroid::StopAccurateListening();
 }
 
 bool ScreenOrientationMessageFilterAndroid::OnMessageReceived(
     const IPC::Message& message) {
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(ScreenOrientationMessageFilterAndroid, message)
-    IPC_MESSAGE_HANDLER(ScreenOrientationHostMsg_StartListening,
-                        OnStartListening)
-    IPC_MESSAGE_HANDLER(ScreenOrientationHostMsg_StopListening,
-                        OnStopListening)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-  return handled;
+  return false;
 }
 
-void ScreenOrientationMessageFilterAndroid::OnStartListening() {
+void ScreenOrientationMessageFilterAndroid::StartListening() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
   ++listeners_count_;
   if (listeners_count_ == 1)
     ScreenOrientationDelegateAndroid::StartAccurateListening();
 }
 
-void ScreenOrientationMessageFilterAndroid::OnStopListening() {
+void ScreenOrientationMessageFilterAndroid::StopListening() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
   DCHECK(listeners_count_ > 0);
   --listeners_count_;
   if (listeners_count_ == 0)