Add logging to TestBrowserDialog::VerifyUi()

Many places in test code call EXPECT_TRUE(VerifyUi()), which only
produces a stack trace and does not tell you which of the conditions in
VerifyUi() aren't met. Adding logging allows us to look at the test logs
and figure out which condition actually failed.

Change-Id: If6f81dac0f10aabdf8125571295f2a55343f93ac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1949452
Auto-Submit: Dana Fried <dfried@chromium.org>
Commit-Queue: Peter Boström <pbos@chromium.org>
Reviewed-by: Peter Boström <pbos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721528}

chrome/browser/ui/test/test_browser_dialog.cc

@@ -94,8 +94,10 @@ bool TestBrowserDialog::VerifyUi() {
   });
   widgets_ = added;
 
-  if (added.size() != 1)
+  if (added.size() != 1) {
+    DLOG(INFO) << "VerifyUi(): Expected 1 added widget; got " << added.size();
     return false;
+  }
 
   views::Widget* dialog_widget = *(added.begin());
 // TODO(https://crbug.com/958242) support Mac for pixel tests.
@@ -114,8 +116,10 @@ bool TestBrowserDialog::VerifyUi() {
     const std::string test_name =
         base::StrCat({test_info->test_case_name(), "_", test_info->name()});
     if (!pixel_diff_->CompareScreenshot(test_name,
-                                        dialog_widget->GetContentsView()))
+                                        dialog_widget->GetContentsView())) {
+      DLOG(INFO) << "VerifyUi(): Pixel compare failed.";
       return false;
+    }
   }
 #endif  // OS_MACOSX
 
@@ -132,7 +136,11 @@ bool TestBrowserDialog::VerifyUi() {
   const gfx::Rect display_work_area =
       screen->GetDisplayNearestWindow(native_window).work_area();
 
-  return display_work_area.Contains(dialog_bounds);
+  const bool dialog_in_bounds = display_work_area.Contains(dialog_bounds);
+  DLOG_IF(INFO, !dialog_in_bounds)
+      << "VerifyUi(): Dialog bounds " << dialog_bounds.ToString()
+      << " outside of display work area " << display_work_area.ToString();
+  return dialog_in_bounds;
 #else
   NOTIMPLEMENTED();
   return false;