Refactor ChooserDialogView to use borders instead of content margins.

chrome/browser/chooser_controller/mock_chooser_controller.cc

Index: chrome/browser/chooser_controller/mock_chooser_controller.cc
diff --git a/chrome/browser/chooser_controller/mock_chooser_controller.cc b/chrome/browser/chooser_controller/mock_chooser_controller.cc
index 9763d8c759ca2d8ef0f670336dae363d3a23faa8..92fc1e1bc398e030ee6783ae19981ced651a6f0c 100644
--- a/chrome/browser/chooser_controller/mock_chooser_controller.cc
+++ b/chrome/browser/chooser_controller/mock_chooser_controller.cc
@@ -14,7 +14,9 @@
 MockChooserController::MockChooserController()
     : ChooserController(nullptr,
                         IDS_USB_DEVICE_CHOOSER_PROMPT_ORIGIN,
-                        IDS_USB_DEVICE_CHOOSER_PROMPT_EXTENSION_NAME) {}
+                        IDS_USB_DEVICE_CHOOSER_PROMPT_EXTENSION_NAME) {
+  set_title_for_testing(base::ASCIIToUTF16("Mock Chooser Dialog"));
+}
 
 MockChooserController::~MockChooserController() {}