DevTools: fix date with version, image for What's New

* Use a customizable header string
* Make png smaller

BUG=682879

Review-Url: https://codereview.chromium.org/2813303004
Cr-Commit-Position: refs/heads/master@{#464662}
(cherry picked from commit 629219e)

NOTRY=true
NOPRESUBMIT=true

Review-Url: https://codereview.chromium.org/2834473002
Cr-Commit-Position: refs/branch-heads/3071@{#66}
Cr-Branched-From: a106f0a-refs/heads/master@{#464641}

third_party/WebKit/LayoutTests/inspector/help/release-note-expected.txt

@@ -4,7 +4,7 @@ Last release note version seen:
 0
 
 Dumping release note text:
-Highlights from March 2017 update
+Highlights from Chrome 100 update
 Improved Performance and Memory panels
 Edit cookies directly from the Application panel
 LEARN MORECLOSE

third_party/WebKit/LayoutTests/inspector/help/release-note.html

@@ -6,7 +6,7 @@
      Help.releaseNoteText = [
          {
              version: 99,
-             date: "March 2017",
+             header: 'Highlights from Chrome 100 update',
              highlights: [
                  {
                      title: 'Improved Performance and Memory panels',

third_party/WebKit/Source/devtools/front_end/help/Help.js

@@ -62,7 +62,7 @@ Help._releaseNoteViewId = 'release-note';
 Help.ReleaseNoteHighlight;
 
 /**
- * @typedef {!{version: number, date: string, highlights: !Array<!Help.ReleaseNoteHighlight>,
+ * @typedef {!{version: number, header: string, highlights: !Array<!Help.ReleaseNoteHighlight>,
  *    link: string}}
  */
 Help.ReleaseNote;

third_party/WebKit/Source/devtools/front_end/help/ReleaseNoteText.js

@@ -12,7 +12,7 @@ var commandMenuShortcut = Host.isMac() ? 'Command + Shift + P' : 'Control + Shif
 Help.releaseNoteText = [
   {
     version: 2,
-    date: 'April 2017',
+    header: 'Highlights from Chrome 59 update',
     highlights: [
       {
         title: 'CSS and JS code coverage',
@@ -49,7 +49,7 @@ Help.releaseNoteText = [
   },
   {
     version: 1,
-    date: 'March 2017',
+    header: 'Highlights from Chrome 58 update',
     highlights: [
       {
         title: 'New Performance and Memory panels',

third_party/WebKit/Source/devtools/front_end/help/ReleaseNoteView.js

@@ -8,7 +8,7 @@ Help.ReleaseNoteView = class extends UI.VBox {
     this.registerRequiredCSS('help/releaseNote.css');
     var releaseNoteElement = this._createReleaseNoteElement(Help.latestReleaseNote());
     var topSection = this.contentElement.createChild('div', 'release-note-top-section');
-    topSection.textContent = Common.UIString(`Highlights from ${Help.latestReleaseNote().date} update`);
+    topSection.textContent = Common.UIString(Help.latestReleaseNote().header);
     this.contentElement.appendChild(releaseNoteElement);
   }