Mouse lock implementation, including the renderer side and the Windows version of the browser side.

content/browser/renderer_host/render_widget_host_view.cc

Index: content/browser/renderer_host/render_widget_host_view.cc
diff --git a/content/browser/renderer_host/render_widget_host_view.cc b/content/browser/renderer_host/render_widget_host_view.cc
index ba714df1100001d56a1f035e2230077564169a15..3722ddc5aa2ebf30b34a5b963afa62177edbe44e 100644
--- a/content/browser/renderer_host/render_widget_host_view.cc
+++ b/content/browser/renderer_host/render_widget_host_view.cc
@@ -4,6 +4,7 @@
 
 #include "content/browser/renderer_host/render_widget_host_view.h"
 
+#include "base/logging.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebScreenInfo.h"
 
 #if defined(OS_MACOSX)
@@ -39,7 +40,9 @@ void RenderWidgetHostView::GetDefaultScreenInfo(
 }
 #endif
 
-RenderWidgetHostView::~RenderWidgetHostView() {}
+RenderWidgetHostView::~RenderWidgetHostView() {
+  DCHECK(!mouse_locked_);
+}
 
 void RenderWidgetHostView::SetBackground(const SkBitmap& background) {
   background_ = background;