[Feedback] Update strings per UX recommendations.

Changes include:
- Omitting trailing period and colons from labels/headers.
- Omitting "optional" text from labels and adding group subheading to indicate optional fields.
- Shorten some strings.

Used camelCase for new string per presubmit guidelines for i18n-content.

BUG=640604
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2293673002
Cr-Commit-Position: refs/heads/master@{#415666}

chrome/app/generated_resources.grd

@@ -7704,16 +7704,16 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <if expr="enable_extensions">
         <!-- Feedback Dialog -->
         <message name="IDS_FEEDBACK_REPORT_PAGE_TITLE" desc="Label showing the title of the page that will be reported">
-          Tell us what's happening.
+          Tell us what's happening
         </message>
         <message name="IDS_FEEDBACK_REPORT_URL_LABEL" desc="Label showing the URL that will be reported">
-          URL (optional):
+          URL
         </message>
         <message name="IDS_FEEDBACK_USER_EMAIL_LABEL" desc="Label showing the e-mail address that will be reported">
-          Email (optional):
+          Email
         </message>
         <message name="IDS_FEEDBACK_SCREENSHOT_LABEL" desc="Label for the screenshot field if current screenshots are being shown">
-          Include this screenshot:
+          Include this screenshot
         </message>
         <message name="IDS_FEEDBACK_INCLUDE_PERFORMANCE_TRACE_CHECKBOX" desc="Checkbox for including system performance data on the bug report dialog box">
           Send performance trace data
@@ -7738,10 +7738,10 @@ Keep your key file in a safe place. You will need it to create new versions of y
           </message>
         </if>
         <message name="IDS_FEEDBACK_ATTACH_FILE_NOTE" desc="Text for describing the maximum size for an attached file">
-          The attached file is uploaded to Google servers for debugging.
+          File will be sent to Google for debugging
         </message>
         <message name="IDS_FEEDBACK_ATTACH_FILE_LABEL" desc="Text for the label for the attached filename">
-          Attach file:
+          Attach file
         </message>
         <message name="IDS_FEEDBACK_READING_FILE" desc="Text to display if reading a file when the user clicks the send report button">
           Reading file..
@@ -7764,7 +7764,7 @@ Keep your key file in a safe place. You will need it to create new versions of y
           Please tell us what is happening before sending the feedback.
         </message>
         <message name="IDS_FEEDBACK_SEND_REPORT" desc="Text for OK button of the send feedback dialog">
-          Send feedback
+          Send
         </message>
         <message name="IDS_FEEDBACK_SYSINFO_PAGE_TITLE" desc="The title of the system information preview page">
           System Information Preview
@@ -7772,6 +7772,9 @@ Keep your key file in a safe place. You will need it to create new versions of y
         <message name="IDS_FEEDBACK_SYSINFO_PAGE_LOADING" desc="The message showing the status of the system information preview page that it is still loading">
           Loading...
         </message>
+        <message name="IDS_FEEDBACK_ADDITIONAL_INFO_LABEL" desc="Text for the group label to indicate that some fields are optional.">
+          Additional info (optional)
+        </message>
 
         <!-- Feedback Dialog SRT Prompt -->
         <message name="IDS_FEEDBACK_SRT_PROMPT_BODY" desc="Body text explaining what the Chrome Software Removal Tool is">

chrome/browser/extensions/api/feedback_private/feedback_private_api.cc

@@ -159,6 +159,7 @@ bool FeedbackPrivateGetStringsFunction::RunSync() {
 #define SET_STRING(id, idr) \
   dict->SetString(id, l10n_util::GetStringUTF16(idr))
   SET_STRING("page-title", IDS_FEEDBACK_REPORT_PAGE_TITLE);
+  SET_STRING("additionalInfo", IDS_FEEDBACK_ADDITIONAL_INFO_LABEL);
   SET_STRING("page-url", IDS_FEEDBACK_REPORT_URL_LABEL);
   SET_STRING("screenshot", IDS_FEEDBACK_SCREENSHOT_LABEL);
   SET_STRING("user-email", IDS_FEEDBACK_USER_EMAIL_LABEL);

chrome/browser/resources/feedback/css/feedback.css

@@ -56,6 +56,10 @@ body {
   width: 100%;
 }
 
+.content #additional-info-label {
+  -webkit-margin-start: 10px;
+}
+
 .content .text-field-container {
   -webkit-align-items: center;
   -webkit-padding-start: 10px;

chrome/browser/resources/feedback/html/default.html

@@ -39,6 +39,9 @@
   </div>
   <div id="content-pane" class="content">
     <textarea id="description-text" aria-labelledby="title-bar"></textarea>
+    <div>
+      <p id="additional-info-label" i18n-content="additionalInfo"><p>
+    </div>
     <div id="page-url" class="text-field-container">
       <label id="page-url-label" i18n-content="page-url"></label>
       <input id="page-url-text" aria-labelledby="page-url-label" type="text">