Fix sizing issues in the tab modal signin flow.

chrome/browser/ui/signin_view_controller_delegate.cc

Index: chrome/browser/ui/signin_view_controller_delegate.cc
diff --git a/chrome/browser/ui/signin_view_controller_delegate.cc b/chrome/browser/ui/signin_view_controller_delegate.cc
index 86ea51762aca517bfb9cb3851a0f5d2b77812d79..f1c8cf513d1488a5d4eada0e47389891290f5325 100644
--- a/chrome/browser/ui/signin_view_controller_delegate.cc
+++ b/chrome/browser/ui/signin_view_controller_delegate.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/ui/signin_view_controller_delegate.h"
 
 #include "base/bind.h"
+#include "base/values.h"
 #include "chrome/browser/ui/signin_view_controller.h"
 #include "chrome/browser/ui/webui/signin/get_auth_frame.h"
 #include "content/public/browser/web_contents.h"
@@ -28,6 +29,10 @@ SigninViewControllerDelegate::SigninViewControllerDelegate(
       "navigationButtonClicked",
       base::Bind(&SigninViewControllerDelegate::HandleNavigationButtonClicked,
                  base::Unretained(this)));
+  web_contents_->GetWebUI()->RegisterMessageCallback(
+      "resizeNativeView",
+      base::Bind(&SigninViewControllerDelegate::HandleResizeNativeView,
+                 base::Unretained(this)));
 }
 
 SigninViewControllerDelegate::~SigninViewControllerDelegate() {}
@@ -69,3 +74,11 @@ void SigninViewControllerDelegate::HandleNavigationButtonClicked(
     CloseModalSignin();
   }
 }
+
+void SigninViewControllerDelegate::HandleResizeNativeView(
+    const base::ListValue* args) {
+  int height;
+  if (args->GetInteger(0, &height)) {

[Dan Beam, 2016/03/18 18:10:08]

double height;
CHECK(args->GetInteger(0, &height));
ResizeNativeView(static_cast<int>(height));

or

double height;
bool success = args->GetInteger(0, &height);
DCHECK(success);
ResizeNativeView(static_cast<int>(height));

[anthonyvd, 2016/03/18 18:53:40]

Done.

+    ResizeNativeView(height);
+  }
+}