Expand width of input/dropdown in Add/Edit Printer UI

- Expand width of inputs and searchable drop downs to 100% of dialog.

Bug: 955173
Test: End to End manual
Change-Id: I27ef20385af45946571c8fe23b2ebc5b79a673a8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1578118Reviewed-by: Bailey Berro <baileyberro@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: jimmy gong <jimmyxgong@chromium.org>
Cr-Commit-Position: refs/heads/master@{#656316}

chrome/browser/resources/settings/printing_page/cups_printer_shared_css.html

@@ -22,7 +22,7 @@
       }
 
       [slot='dialog-body'] .settings-box cr-input {
-        width: 270px;
+        width: 100%;
       }
 
       /* The only input that has error-message are at the end, so we don't
@@ -33,16 +33,16 @@
       }
 
       [slot='dialog-body'] .settings-box .md-select {
-        width: 270px;
+        width: 100%;
       }
 
       [slot='dialog-body'] .settings-box .printer-name-input {
-        width: 450px;
+        width: 100%;
       }
 
       [slot='dialog-body'] .settings-box .browse-file-input {
         width: auto;
-        --cr-input-width: 270px;
+        --cr-input-width: 383px;
       }
 
       [slot='dialog-body'] .settings-box .browse-button {