Fix help text size calculation for password gen bubble on Mac.

chrome/browser/ui/cocoa/autofill/password_generation_popup_view_cocoa.mm

Index: chrome/browser/ui/cocoa/autofill/password_generation_popup_view_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/autofill/password_generation_popup_view_cocoa.mm b/chrome/browser/ui/cocoa/autofill/password_generation_popup_view_cocoa.mm
index 8fc9e528592031b46bf9cb9c44cc90a75a224610..79fefcd73077a9fb3378e109b07259e6114b402f 100644
--- a/chrome/browser/ui/cocoa/autofill/password_generation_popup_view_cocoa.mm
+++ b/chrome/browser/ui/cocoa/autofill/password_generation_popup_view_cocoa.mm
@@ -164,11 +164,12 @@ NSColor* HelpLinkColor() {
       autofill::kPopupBorderThickness;
 
   width = std::max(width, (CGFloat)controller_->GetMinimumWidth());
+  CGFloat contentWidth = width - (2 * controller_->kHorizontalPadding);
 
   CGFloat height =
       autofill::kPopupBorderThickness +
       controller_->kHelpVerticalPadding +
-      [self helpSizeForPopupWidth:width].height +
+      [self helpSizeForPopupWidth:contentWidth].height +
       controller_->kHelpVerticalPadding +
       autofill::kPopupBorderThickness;