Make the MediaRouterDialogDelegate set initial dialog size in OSX

chrome/browser/ui/webui/media_router/media_router_dialog_controller_impl.cc

Index: chrome/browser/ui/webui/media_router/media_router_dialog_controller_impl.cc
diff --git a/chrome/browser/ui/webui/media_router/media_router_dialog_controller_impl.cc b/chrome/browser/ui/webui/media_router/media_router_dialog_controller_impl.cc
index ad69808749ce7dd72bfd8aedcdc801c2c8f82e9b..ae65f141d43e5d21033edda6530ba46911a82cdf 100644
--- a/chrome/browser/ui/webui/media_router/media_router_dialog_controller_impl.cc
+++ b/chrome/browser/ui/webui/media_router/media_router_dialog_controller_impl.cc
@@ -77,7 +77,21 @@ class MediaRouterDialogDelegate : public WebDialogDelegate {
     // MediaRouterUI adds its own message handlers.
   }
 
-  void GetDialogSize(gfx::Size* size) const override;
+  void GetDialogSize(gfx::Size* size) const override {
+    DCHECK(size);
+#if defined(OS_MACOSX)
+    // When WebDialogConstrainedWindowSheet::updateSheetPosition() calls
+    // GetDialogSize() in OSX, we need to set |size| to be non-empty. Otherwise
+    // the dialog may fail to show.
+    if (size->IsEmpty())
+      *size = gfx::Size(kWidth, kMinHeight);
+#endif
+    // GetDialogSize() is called when the dialog is created or the browser
+    // window resizes. We may want to update the maximum height of the dialog
+    // and scale the WebUI to the new height. |size| is not set (except for in
+    // OSX) because the dialog is auto-resizeable.
+    controller_->UpdateMaxDialogSize();
+  }
 
   std::string GetDialogArgs() const override {
     return std::string();
@@ -106,14 +120,6 @@ class MediaRouterDialogDelegate : public WebDialogDelegate {
   DISALLOW_COPY_AND_ASSIGN(MediaRouterDialogDelegate);
 };
 
-void MediaRouterDialogDelegate::GetDialogSize(gfx::Size* size) const {
-  DCHECK(size);
-  // GetDialogSize() is called when the browser window resizes. We may want to
-  // update the maximum height of the dialog and scale the WebUI to the new
-  // height. |size| is not set because the dialog is auto-resizeable.
-  controller_->UpdateMaxDialogSize();
-}
-
 }  // namespace
 
 // static