Revert 90395 - Remove the lock in GtkNativeViewManager.

Since removing the X11 background thread, this class is now only
used from the UI thread.

Review URL: http://codereview.chromium.org/7187026

TBR=tony@chromium.org
Review URL: http://codereview.chromium.org/7235020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@90510 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 19 insertions, 4 deletions

diff --git a/ui/gfx/gtk_native_view_id_manager.h b/ui/gfx/gtk_native_view_id_manager.h
index aad39ad..2a651a0 100644
--- a/ui/gfx/gtk_native_view_id_manager.h
+++ b/ui/gfx/gtk_native_view_id_manager.h
@@ -10,7 +10,6 @@
 
 #include "base/memory/singleton.h"
 #include "base/synchronization/lock.h"
-#include "base/threading/non_thread_safe.h"
 #include "ui/gfx/native_widget_types.h"
 
 typedef unsigned long XID;
@@ -29,13 +28,15 @@ struct _GtkPreserveWindow;
 //
 // Thus, we have this object. It produces random NativeViewIds from GtkWidget
 // pointers and observes the various signals from the widget for when an X
-// window is created, destroyed etc. Thus it provides a mapping from
-// NativeViewIds to the current XID for that widget.
-class GtkNativeViewManager : public base::NonThreadSafe {
+// window is created, destroyed etc. Thus it provides a thread safe mapping
+// from NativeViewIds to the current XID for that widget.
+class GtkNativeViewManager {
  public:
   // Returns the singleton instance.
   static GtkNativeViewManager* GetInstance();
 
+  // Must be called from the UI thread:
+  //
   // Return a NativeViewId for the given widget and attach to the various
   // signals emitted by that widget. The NativeViewId is pseudo-randomly
   // allocated so that a compromised renderer trying to guess values will fail
@@ -43,6 +44,8 @@ class GtkNativeViewManager : public base::NonThreadSafe {
   // lifetime of the GtkWidget.
   gfx::NativeViewId GetIdForWidget(gfx::NativeView widget);
 
+  // May be called from any thread:
+  //
   // xid: (output) the resulting X window ID, or 0
   // id: a value previously returned from GetIdForWidget
   // returns: true if |id| is a valid id, false otherwise.
@@ -51,9 +54,14 @@ class GtkNativeViewManager : public base::NonThreadSafe {
   // |*xid| is set to 0.
   bool GetXIDForId(XID* xid, gfx::NativeViewId id);
 
+  // May be called from the UI thread:
+  //
   // Same as GetXIDForId except it returns the NativeView (GtkWidget*).
   bool GetNativeViewForId(gfx::NativeView* xid, gfx::NativeViewId id);
 
+  // Must be called from the UI thread because we may need the associated
+  // widget to create a window.
+  //
   // Keeping the XID permanent requires a bit of overhead, so it must
   // be explicitly requested.
   //
@@ -62,10 +70,14 @@ class GtkNativeViewManager : public base::NonThreadSafe {
   // returns: true if |id| is a valid id, false otherwise.
   bool GetPermanentXIDForId(XID* xid, gfx::NativeViewId id);
 
+  // Can be called from any thread.
   // Will return false if the given XID isn't permanent or has already been
   // released.
   bool AddRefPermanentXID(XID xid);
 
+  // Must be called from the UI thread because we may need to access a
+  // GtkWidget or destroy a GdkWindow.
+  //
   // If the widget associated with the XID is still alive, allow the widget
   // to destroy the associated XID when it wants. Otherwise, destroy the
   // GdkWindow associated with the XID.
@@ -91,6 +103,9 @@ class GtkNativeViewManager : public base::NonThreadSafe {
 
   gfx::NativeViewId GetWidgetId(gfx::NativeView id);
 
+  // protects native_view_to_id_ and id_to_info_
+  base::Lock lock_;
+
   // If asked for an id for the same widget twice, we want to return the same
   // id. So this records the current mapping.
   std::map<gfx::NativeView, gfx::NativeViewId> native_view_to_id_;